@article{miller_silverberg_eischen_miller_2024, title={How Schwarzschild could have discovered and fixed the problem with his metric}, volume={37}, ISSN={["2371-2236"]}, DOI={10.4006/0836-1398-37.1.74}, abstractNote={Karl Schwarzschild's landmark paper revealed the first ever exact solution to Einstein's gravitational field equation. This was a major scientific achievement. However, his solution for the metric of a spherically symmetric spacetime is different than the one found in textbooks today—because
 Schwarzschild assumed, like in Newtonian gravity, that only one singularity could exist. Given the newness of Einstein's general theory of relativity and the existing paradigm of Newtonian gravity, his assumption was natural. While other authors have previously pointed out this shortcoming
 and corrected it, the contribution of this paper is to show how Schwarzschild might have discovered it himself. A simple geometric proof indicates how Schwarzschild, with a different assignment of a single constant of integration, would have arrived at the metric found in textbooks today.}, number={1}, journal={PHYSICS ESSAYS}, author={Miller, Lane R. and Silverberg, Larry M. and Eischen, Jeffrey W. and Miller, Samuel R.}, year={2024}, month={Mar}, pages={74–79} }
 @article{silverberg_eischen_2023, title={Trajectory of a Spacecraft When It Passes by a Gravitational Body During Interstellar Travel}, volume={9}, ISSN={["1533-6794"]}, DOI={10.2514/1.A35684}, abstractNote={Interstellar space missions will require spacecraft that travel at relativistic speeds. Furthermore, their trajectories will be influenced by gravitational sources. Accordingly, this paper applies to interstellar missions a recently developed formulation of relativistic mechanics that predicts a spacecraft’s trajectory when it passes by a gravitational source at a relativistic speed. The formulation, called spacetime impetus, is unique in that it employs a relativistic universal law of gravitation that does not explicitly require general relativity while producing precisely the same results. Based on these developments, an analyst can now update nonrelativistic mission planning codes to give them general relativistic capabilities. It requires augmenting the code with relativistic velocities and relativistic accelerations, the replacement of the universal law of gravitation with a relativistic universal law of gravitation, and setting up Lorentz transformations between frames.}, journal={JOURNAL OF SPACECRAFT AND ROCKETS}, author={Silverberg, Larry M. and Eischen, Jeffrey W.}, year={2023}, month={Sep} }
 @article{silverberg_eischen_2021, title={Theory of spacetime impetus}, volume={34}, url={http://dx.doi.org/10.4006/0836-1398-34.4.548}, DOI={10.4006/0836-1398-34.4.548}, abstractNote={This article introduces the theory of spacetime impetus (SI). The theory unites Newtonian theory (NT) and the theory of general relativity (GR). To develop SI, we reformulated NT in spacetime and replaced the particle primitive in NT with the fragment of energy primitive in field theory.
 SI replaces Newton’s second law F = ma governing the motion of particles, where F, m, and a are, respectively, interaction force, mass, and acceleration, with the change equation P = k governing the motion of fragments of energy,
 where P and k are, respectively, action force and the curvature of a path in spacetime. To verify SI, we conducted three tests: Test 1 predicted the precession angles of Mercury and Jupiter, test 2 predicted the bending angle of light as it grazes the surface of the sun, and
 test 3 predicted the radius of the photon sphere. All three tests were in agreement with GR, the third corresponding to strong Riemannian curvature in GR. The equations of motion in SI are in terms of Cartesian coordinates and time and are relatively simple to solve. Undergraduate students
 in science and engineering and others with similar mathematical skills can validate the results for themselves.}, number={4}, journal={Physics Essays}, publisher={Physics Essays Publication}, author={Silverberg, Larry M. and Eischen, Jeffrey W.}, year={2021}, month={Dec}, pages={548–563} }
 @article{rao_eischen_2020, title={Failure analysis of fretting fracture in frame rails of heavy duty trucks - Case study}, volume={113}, ISSN={["1873-1961"]}, DOI={10.1016/j.engfailanal.2020.104544}, abstractNote={This paper analyzed fatigue fracture of a frame rail during accelerated endurance test of a heavy duty truck. This fracture was noted in an area of high shear stresses where contact and fretting fatigue was suspected. A cross section through the fracture initiation site showed areas of surface contact wear in the microstructure. Fretting wear resulted in crack initiation and propagated to form a through crack under reverse bending fatigue crack growth mechanism. A combination of crack growth simulation tool (FRANC3D) and finite element analysis solver (MSC NASTRAN) was used and automated to handle multiple crack growth iterations. The simulation results obtained showed good correlation to failure crack path and cycles to failure. These simulation results were also used to understand the root cause of failure, identify critical parameters causing failure and recommend design modifications to prevent fretting fatigue in frame of heavy duty trucks. A modified design using the proposed simulation methodology was identified and was shown to provide improved frame durability.}, journal={ENGINEERING FAILURE ANALYSIS}, author={Rao, Vinay N. and Eischen, Jeffrey W.}, year={2020}, month={Jul} }
 @article{silverberg_eischen_2020, title={On a new field theory formulation and a space-time adjustment that predict the same precession of Mercury and the same bending of light as general relativity}, volume={33}, ISSN={["2371-2236"]}, DOI={10.4006/0836-1398-33.4.489}, abstractNote={This article introduces a new field theory formulation. The new field theory formulation recognizes vector continuity as a general principle and begins with a field that satisfies vector continuity equations. Next, independent of the new formulation, this article introduces a new space-time
 adjustment. Then, we solve the one-body gravitational problem by applying the space-time adjustment to the new field theory formulation. With the space-time adjustment, the new formulation predicts precisely the same precession of Mercury and the same bending of light as general relativity.
 The reader will find the validating calculations to be simple. The equations of motion that govern the orbital equations are in terms of Cartesian coordinates and time. An undergraduate college student, with direction, can perform the validations.}, number={4}, journal={PHYSICS ESSAYS}, author={Silverberg, Larry M. and Eischen, Jeffrey W.}, year={2020}, month={Dec}, pages={489–512} }
 @article{rao_eischen_2016, title={Failure analysis of mixed mode crack growth in heavy duty truck frame rail}, volume={5-6}, ISSN={2213-2902}, url={http://dx.doi.org/10.1016/j.csefa.2016.03.002}, DOI={10.1016/j.csefa.2016.03.002}, abstractNote={A failure analysis investigation was performed on a fractured heavy duty truck frame rail obtained during endurance track testing. The fracture observed was on the frame web within the torque rod connection to the rear drive axle of the vehicle. This section of frame experiences multi-axial loading conditions including out-of-plane bending, twisting and shear under road loads. Metallographic examination revealed micro-cracks on the edges of an open hole located in an area of high stress concentration. This manufacturing defect acted as a stress raiser and resulted in fatigue crack initiation. Simulation of crack growth on frame rail using dynamic loads from a full vehicle model was completed. After careful analysis it was concluded that the failure occurred due to an aggressively drilled open hole which created small crack initiations in a high stress-state location of the frame. This resulted in extensive curvilinear crack growth under dynamic loads of the vehicle.}, journal={Case Studies in Engineering Failure Analysis}, publisher={Elsevier BV}, author={Rao, Vinay N. and Eischen, Jeffrey W.}, year={2016}, month={Apr}, pages={67–74} }
 @article{stamps_eischen_huang_2016, title={Particle- and crack-size dependency of lithium-ion battery materials LiFePO₄}, volume={3}, ISSN={2372-0484}, url={http://dx.doi.org/10.3934/matersci.2016.1.190}, DOI={10.3934/matersci.2016.1.190}, abstractNote={Lithium-ion batteries have become a widely-used commodity for satisfying the world’s mobile power needs. However, the mechanical degradation of lithium-ion batteries initiated by micro cracks is considered to be a bottleneck for advancing the current technology. This study utilizes a finite element method-based virtual crack closure technique to obtain particle- and crack-size-dependent estimates of mixed-mode energy release rates and stress intensity factors. Interfacial cracks in orthotropic bi-materials are considered in the current study, whereas the crack extension along the interface is assumed. The results show that energy release rate, stress intensity factor, and the propensity of crack extension are particle- and crack-size- dependent. In particular, our results show that for smaller plate-like LiFePO 4 particles (100 nm × 45 nm), a crack has lesser tendency to extend if crack-to-particle size is less than 0.2, and for 200 nm × 90 nm particles, similar results are obtained for crack-to-particle sizes of less than 0.15. However, for larger particles (500 nm × 225 nm), it requires an almost flawless particle to have no crack extension. Therefore, the current study provides insight into the fracture mechanics of LiFePO 4 and the associated crack-to-particle size dependency to prevent crack extensions.}, number={1}, journal={AIMS Materials Science}, publisher={American Institute of Mathematical Sciences (AIMS)}, author={Stamps, Michael A. and Eischen, Jeffrey W. and Huang, Hsiao-Ying Shadow}, year={2016}, pages={190–203} }
 @article{kenkare_lamar_pandurangan_eischen_2008, title={Enhancing accuracy of drape simulation. Part I: Investigation of drape variability via 3D scanning}, volume={99}, ISSN={["1754-2340"]}, DOI={10.1080/00405000701489222}, abstractNote={Abstract The objective of this two part paper is to present a method of enhancing accuracy of fabric drape simulation using commercially available software. In Part I, we report results of an investigation of drape variability for a set of fabrics having varied mechanical properties, an essential step in defining accuracy for drape simulation. Results illustrate that fabric drape behaviour is highly variable and thus provide no single drape configuration to target with simulation. Development of a revolutionary method for capturing drape of actual fabrics and measuring that drape in a virtual three-dimensional (3D) environment is also presented. The method allows identical drape measurement processes to be implemented for actual and simulated fabrics and provides opportunity for use of additional measures to assess fabric drape in three dimensions. The accomplishments presented in this paper are utilized to demonstrate, in Part II, development of a relationship that enhances realism of particle model simulations generated using the commercial drape simulation software.}, number={3}, journal={JOURNAL OF THE TEXTILE INSTITUTE}, author={Kenkare, Narahari and Lamar, Traci A. M. and Pandurangan, Pradeep and Eischen, Jeffrey}, year={2008}, pages={211–218} }
 @article{pandurangan_eischen_kenkare_lamar_2008, title={Enhancing accuracy of drape simulation. Part II: Optimized drape simulation using industry-specific software}, volume={99}, ISSN={["1754-2340"]}, DOI={10.1080/00405000701489198}, abstractNote={Abstract Three-dimensional virtual representations of fabrics are done based on mass-spring modeling, which represents cloth as a mesh of particles connected by springs. The spring constant values input to the model correspond to the mechanical properties of the modeled fabric. For apparel, these representations have been incorporated into commercial software packages for use in design and development of garments. However, fabric mechanical property values as derived using industry test methods cannot be input directly into the commercial software to produce simulations that accurately represent a specific fabric. A systematic way of selecting input parameters to a particle model was developed by comparing the drape of circular fabric samples whose mechanical properties were measured by the Kawabata evaluation system to simulations produced by the particle model using methods developed in Part I of this paper. Also, a relationship was developed between measured fabric mechanical properties and simulation input parameters and then tested on simulations of apparel samples.}, number={3}, journal={JOURNAL OF THE TEXTILE INSTITUTE}, author={Pandurangan, Pradeep and Eischen, Jeffrey and Kenkare, Narahari and Lamar, Traci A. M.}, year={2008}, pages={219–226} }
 @article{jernigan_buckner_eischen_2007, title={Finite element modeling of the left atrium to facilitate the design of an endoscopic atrial retractor}, volume={129}, ISSN={["1528-8951"]}, DOI={10.1115/1.2801650}, abstractNote={Abstract
               With the worldwide prevalence of cardiovascular diseases, much attention has been focused on simulating the characteristics of the human heart to better understand and treat cardiac disorders. The purpose of this study is to build a finite element model of the left atrium (LA) that incorporates detailed anatomical features and realistic material characteristics to investigate the interaction of heart tissue and surgical instruments. This model is used to facilitate the design of an endoscopically deployable atrial retractor for use in minimally invasive, robotically assisted mitral valve repair. Magnetic resonance imaging (MRI) scans of a pressurized explanted porcine heart were taken to provide a 3D solid model of the heart geometry, while uniaxial tensile tests of porcine left atrial tissue were conducted to obtain realistic material properties for noncontractile cardiac tissue. A finite element model of the LA was constructed using ANSYS™ Release 9.0 software and the MRI data. The Mooney–Rivlin hyperelastic material model was chosen to characterize the passive left atrial tissue; material constants were derived from tensile test data. Finite element analysis (FEA) models of a CardioVations Port Access™ retractor and a prototype endoscopic retractor were constructed to simulate interaction between each instrument and the LA. These contact simulations were used to compare the quality of retraction between the two instruments and to optimize the design of the prototype retractor. Model accuracy was verified by comparing simulated cardiac wall deflections to those measured by MRI. FEA simulations revealed that peak forces of approximately 2.85N and 2.46N were required to retract the LA using the Port Access™ and prototype retractors, respectively. These forces varied nonlinearly with retractor blade displacement. Dilation of the atrial walls and rigid body motion of the chamber were approximately the same for both retractors. Finite element analysis is shown to be an effective tool for analyzing instrument/tissue interactions and for designing surgical instruments. The benefits of this approach to medical device design are significant when compared to the alternatives: constructing prototypes and evaluating them via animal or clinical trials.}, number={6}, journal={JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME}, author={Jernigan, S. R. and Buckner, G. D. and Eischen, J. W.}, year={2007}, month={Dec}, pages={825–837} }
 @article{eischen_monsivais_2007, title={Special issue - Ninth Pan American Congress of Applied Mechanics - Preface}, volume={2}, ISSN={["1559-3959"]}, DOI={10.2140/jomms.2007.2.1395}, abstractNote={The aim of the sponsors of the 9th Pan American Congress of Applied Mechanics (PACAM IX) was to promote progress in the broad field of mechanics by (1) exposing mature engineers and scientists, as well as advanced graduate students, to new research findings, techniques, and problems, and (2) providing opportunities for personal interactions through formal presentations and informal conversations.The meetings are traditionally held every two years in a Latin American venue, at a time when few other conferences are scheduled.The previous Congresses were held in Rio de Janeiro, Brazil (}, number={8}, journal={JOURNAL OF MECHANICS OF MATERIALS AND STRUCTURES}, author={Eischen, Jeffrey W. and Monsivais, Guillermo}, year={2007}, month={Oct}, pages={1395–1395} }
 @inproceedings{eischen_2006, title={A Study of the Relationship Between Buckling and Wrinkling of Membranes}, booktitle={Proceedings of the Ninth Pan American Congress of Applied Mechanics}, author={Eischen, J.W.}, year={2006}, month={Jan} }
 @inproceedings{eischen_lankalapalli_2004, title={Optimal Pick-up Locations for Transport and Handling of Limp Materials}, booktitle={Proceedings of the Eighth Pan American Congress of Applied Mechanics}, author={Eischen, J.W. and Lankalapalli, S.}, year={2004}, month={Jan} }
 @article{palmer_dessent_mulling_usher_grant_eischen_kingon_franzon_2004, title={The design and characterization of a novel piezoelectric transducer-based linear motor}, volume={9}, ISSN={["1941-014X"]}, DOI={10.1109/TMECH.2004.828647}, abstractNote={Before microminiature robots can be realized, new direct drive micromotor systems must be developed. In this research, a linear motor system for a miniature jumping robot was desired. However, current systems must display better force/torque characteristics than is currently available. This paper deals with the design, construction, and testing, of a macro-scale, unidirectional, direct drive linear piezomotor that operates like an inchworm. It uses a parallel arrangement of unimorph piezoelectric transducers, in conjunction with passive mechanical latches, to perform work on a coil spring. Experimental results showed that the linear piezomotor achieved a maximum no-load velocity of 161 mm/s, and a blocked force of 14 N, at a drive signal frequency of 100 Hz. Thereafter, back slip in the latch assembly restricted the forward motion. Based on the results obtained with the macro-level linear piezomotor, it is concluded that smaller direct drive piezomotor designs based on unimorph piezoelectric transducers are achievable. System scalability will be addressed in a future publication.}, number={2}, journal={IEEE-ASME TRANSACTIONS ON MECHATRONICS}, author={Palmer, JA and Dessent, B and Mulling, JF and Usher, T and Grant, E and Eischen, JW and Kingon, AI and Franzon, PD}, year={2004}, month={Jun}, pages={392–398} }
 @inproceedings{palmer_mulling_dessent_grant_eischen_gruverman_kingon_franzon_2004, title={The design, fabrication, and characterization of millimeter scale motors for miniature direct drive robots}, ISBN={0780382323}, ISSN={1050-4729}, url={http://dx.doi.org/10.1109/robot.2004.1302454}, DOI={10.1109/robot.2004.1302454}, abstractNote={This paper reports on research into miniature, direct drive, high force/torque motors to support insect-sized mobile robotic platforms. The primary focus is on scalable motors based on piezoelectric transducers. The contributions of this work include: (1) the design, analysis, and characterization of a miniature mode conversion rotary ultrasonic motor based on a piezoelectric stack transducer; this produced a static torque density of 0.37 Nm/kg, (2) a millimeter scale linear piezometer, constructed with a parallel arrangement of annular stressed unimorph piezoelectric transducers and passive latches, exhibited 0.23 N of blocked force, and (3) simulation data is presented that compares these motor concepts to commercial systems in the context of scalability. Results suggest that smaller versions of the rotary ultrasonic motor would possess a static torque density seven times that of a commercial 3-mm electromagnetic system. This technology shows promise for driving the platform.}, booktitle={IEEE International Conference on Robotics and Automation, 2004. Proceedings. ICRA '04. 2004}, publisher={IEEE}, author={Palmer, J.A. and Mulling, J.F. and Dessent, B. and Grant, E. and Eischen, J.W. and Gruverman, A. and Kingon, A.I. and Franzon, P.D.}, year={2004}, pages={4668–4673} }
 @inproceedings{morrisey_eischen_dow_2003, place={Portland, OR}, title={Design and Analysis of Press and Shrink Fit Joints}, booktitle={Proceedings of the American Society for Precision Engineering Conference}, author={Morrisey, P. and Eischen, J.W. and Dow, T.A.}, year={2003}, month={Oct} }
 @article{lankalapalli_eischen_2003, title={Optimal pick-up locations for transport and handling of limp materials - Part I: One-dimensional strips}, volume={73}, ISSN={["1746-7748"]}, DOI={10.1177/004051750307300907}, abstractNote={Pick-up locations are obtained on strips of limp material that minimize a measure of deformation (strain energy). The strips are modeled as continuous beams subjected to a uniformly distributed load using small and large deflection beam theories. Pick-up locations correspond to n support locations of the continuous beam. Strain energy is computed from a finite element solution, and optimal locations are obtained by solving unconstrained and bound constrained optimization problems. Results are in terms of a nondimensional number that characterizes the flexibility of the beam and are applicable to a wide range of limp materials. Some results for fabric strips are also presented.}, number={9}, journal={TEXTILE RESEARCH JOURNAL}, author={Lankalapalli, S and Eischen, JW}, year={2003}, month={Sep}, pages={787–796} }
 @article{lankalapalli_eischen_2003, title={Optimal pick-up locations for transport and handling of limp materials - Part II: Two-dimensional parts}, volume={73}, ISSN={["0040-5175"]}, DOI={10.1177/004051750307301004}, abstractNote={ Pick-up locations are obtained on two-dimensional limp parts that minimize a measure of deformation (strain energy). The parts are modeled as shells undergoing arbitrarily large deformations and rotations by a geometrically exact nonlinear shell finite element formulation. The strain energy is computed from the finite element solution for deforma tion, and the optimal locations are obtained by solving a bound constrained optimization problem. Results are given for various two-dimensional shapes. }, number={10}, journal={TEXTILE RESEARCH JOURNAL}, author={Lankalapalli, S and Eischen, JW}, year={2003}, month={Oct}, pages={867–874} }
 @inproceedings{eischen_love_dow_scattergood_2002, place={Temuco, Chile}, title={Laser Scribing for Use as a Precision Shaping Technique}, booktitle={Proceedings of the Seventh Pan American Congress of Applied Mechanics}, author={Eischen, J.W. and Love, B.M. and Dow, T.A. and Scattergood, R.O.}, year={2002}, month={Jan} }
 @inproceedings{austin_love_dow_eischen_scattergood_2000, title={Bending Deflections Due to Scribe-Induced Residual Stress}, booktitle={Proceedings of the American Society for Precision Engineering Conference}, author={Austin, B. and Love, B. and Dow, T. and Eischen, J.W. and Scattergood, R.}, year={2000} }
 @inbook{bigliani_eischen_2000, title={Collision Detection in Cloth Modeling}, booktitle={Cloth Modeling and Animation}, author={Bigliani, R. and Eischen, J.W.}, editor={Peters, A.K.Editor}, year={2000} }
 @inbook{eischen_bigliani_2000, place={Natick, Massachusetts}, title={Continuum Versus Particle Representations}, ISBN={9781568810904 9781439863947 9780429065095}, booktitle={Cloth modeling and animation}, publisher={A.K. Peters}, author={Eischen, J.W. and Bigliani, R.}, editor={House, D. and Breen, D.E.Editors}, year={2000} }
 @inproceedings{lankalapalli_eischen_2000, place={New York}, title={Optimal Pickup Locations for Fabric Handling}, ISBN={9780791819173}, booktitle={Mechanics in biology : presented at the 2000 ASME International Mechanical Engineering Congress and Exposition, November 5-10, 2000, Orlando, Florida}, publisher={American Society of Mechanical Engineers}, author={Lankalapalli, S. and Eischen, J.W.}, year={2000}, month={Nov} }
 @inproceedings{ross_lange_eischen_1999, place={Virginia Beach, VA}, title={Multidiscipline Analysis of a Fatal LPG Tank Rupture}, booktitle={Proceedings of the 53rd Meeting of the Society for Machinery Failure Prevention Technology}, author={Ross, B. and Lange, C. and Eischen, J.W.}, year={1999} }
 @inproceedings{bauer-kurz_eischen_1999, place={New London, NH}, title={The Mechanics of Removing Staple Crimp}, author={Bauer-Kurz, I. and Eischen, J.W.}, year={1999}, month={Jul} }
 @article{lamattina_klang_eischen_1998, title={A study of solutions for the anisotropic plate subjected to a concentrated force}, volume={65}, ISSN={["0021-8936"]}, DOI={10.1115/1.2789039}, abstractNote={One of the objectives of this brief note is to present all three solutions and show how they are applied to the boundary element method formulation. Secondly, differences between these solutions are illustrated and discussed. The implications of these discrepancies is examined for the infinite plate as well as typical boundary value problem}, number={1}, journal={JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME}, author={LaMattina, B and Klang, EC and Eischen, JW}, year={1998}, month={Mar}, pages={273–276} }
 @inproceedings{eischen_1998, title={Computer Modeling of Fabric Drape}, booktitle={Proceedings of the 35th Annual Society of Engineering Science Conference}, author={Eischen, J.W.}, year={1998} }
 @inproceedings{eischen_1998, title={Drape Modeling of Cloth}, booktitle={Course 31- Cloth and Clothing in Computer Graphics}, author={Eischen, J.W.}, year={1998} }
 @article{wang_eischen_silverberg_1998, title={On control and optimization of elastic multilink mechanisms}, volume={67}, ISSN={["0045-7949"]}, DOI={10.1016/s0045-7949(98)00060-1}, abstractNote={This paper presents a simple method for control of nonlinear elastic multilink mechanisms. The associated control law consists of open and closed loop components. The open loop component produces the desired overall rigid body motion, while the closed loop component suppresses the elastic motion relative to rigid body motion. Both the control law and the structural dynamics are referred to an inertial coordinate system. As a consequence, the control forces and control moments are easily simulated in a dynamic finite element analysis program. A series of numerical simulations illustrate the generality of this new method.}, number={6}, journal={COMPUTERS & STRUCTURES}, author={Wang, HL and Eischen, JW and Silverberg, LM}, year={1998}, month={Jun}, pages={483–502} }
 @inproceedings{eischen_clifton_1997, title={Optimum Manipulation Strategies for Limp Fabric Materials}, booktitle={Proceedings of the Fifth Pan American Congress of Applied Mechanics Conference}, author={Eischen, J.W. and Clifton, W.}, year={1997} }
 @article{tierney_eischen_1997, title={Residual stress analysis of bimaterial strips under multiple thermal loading}, volume={119}, ISSN={["1043-7398"]}, DOI={10.1115/1.2792250}, abstractNote={The residual stress distribution in bimaterial beams induced by multiple thermal loadings has been investigated. Three models for the nonlinear stress-strain material behavior were considered: bilinear elastic-plastic, power law elastic-plastic, and power law purely plastic. The equations governing equilibrium, compatibility of strain, and stress-strain for the bimaterial configuration make up a system of nonlinear algebraic equations which is solved numerically. The elastic-plastic power law model leads to stress discontinuity in the layers. The other two models have been verified with a finite element analysis. Several examples are included using materials common to the microelectronics industry.}, number={4}, journal={JOURNAL OF ELECTRONIC PACKAGING}, author={Tierney, JW and Eischen, JW}, year={1997}, month={Dec}, pages={281–287} }
 @article{eischen_deng_clapp_1996, title={Finite-element modeling and control of flexible fabric parts}, volume={16}, ISSN={["0272-1716"]}, DOI={10.1109/38.536277}, abstractNote={Software based on nonlinear shell theory can simulate 3D motions related to real fabric-manufacturing processes. This simulation capability advances the technologies necessary for automating the textile and apparel industries.}, number={5}, journal={IEEE COMPUTER GRAPHICS AND APPLICATIONS}, author={Eischen, JW and Deng, SG and Clapp, TG}, year={1996}, month={Sep}, pages={71–80} }
 @inproceedings{eischen_reagan_1996, title={Thermal Loading of Bimaterial BeamsElastic Plastic Response}, booktitle={Proceedings of the XVIII Southeastern Conference on Theoretical and Applied Mechanics}, author={Eischen, J.W. and Reagan, S.}, year={1996} }
 @inproceedings{eischen_torquato_1995, title={Determining Elastic Behavior of Composites by the Boundary Element Method}, booktitle={Proceedings of the Fourth Pan American Congress of Applied Mechanics}, author={Eischen, J.W. and Torquato, S.}, year={1995} }
 @article{mcwaters_clapp_eischen_1994, title={Automated Apparel Processing: Computer Simulation of Fabric Deformation for the Design of Equipment}, volume={6}, ISSN={0955-6222}, url={http://dx.doi.org/10.1108/09556229410074600}, DOI={10.1108/09556229410074600}, abstractNote={Introduces and evaluates a finite‐element computer model which predicts the bending behaviour of fabric in contact with a surface, in order to optimize the design of equipment used for automated processing of apparel. Describes how simulations were executed for all combinations of eight fabrics and three contact surfaces, and presents the experimental results obtained for similar conditions and fabrics. Proves the validity of the computer model by comparing the experimental results with those obtained by simulation. Describes how the computer model could be used to choose the optimum diameter of a fabric feeder picking roller.}, number={5}, journal={International Journal of Clothing Science and Technology}, publisher={Emerald}, author={McWaters, S.D. and Clapp, T.G. and Eischen, J.W.}, year={1994}, month={Dec}, pages={30–38} }
 @article{eischen_torquato_1993, title={Determining elastic behavior of composites by the boundary element method}, volume={74}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.354132}, DOI={10.1063/1.354132}, abstractNote={The boundary element method is applied to determine the effective elastic moduli of continuum models of composite materials. In this paper, we specialize to the idealized model of hexagonal arrays of infinitely long, aligned cylinders in a matrix (a model of a fiber-reinforced material) or a thin-plate composite consisting of hexagonal arrays of disks in a matrix. Thus, one need only consider two-dimensional elasticity, i.e., either plane-strain or plane-stress elasticity. This paper examines a variety of cases in which the inclusions are either stiffer or weaker than the matrix for a wide range of inclusion volume fractions φ2. Our comprehensive set of simulation data for the elastic moduli are tabulated. Using the boundary element method, a key microstructural parameter η2 that arises in rigorous three-point bounds on the effective shear modulus is also computed. Our numerical simulations of the elastic moduli for the hexagonal array are compared to rigorous two-point and three-point bounds on the respective effective properties. In the extreme instances of either superrigid particles or voids, we compare analytical relations for the elastic moduli near dilute and close packing limits to our simulation results.}, number={1}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Eischen, J. W. and Torquato, S.}, year={1993}, month={Jul}, pages={159–170} }
 @inproceedings{eischen_reagan_1993, title={Elastic Plastic Analysis of Bimaterial Beams with Strain Hardening}, booktitle={Proceedings of the 1993 ASME Design Technical Conference}, author={Eischen, J.W. and Reagan, S.}, year={1993} }
 @inproceedings{eischen_reagan_1993, title={Elastic Plastic Analysis of Bimaterial Beams with Strain Hardening-Multiple Yield Sites}, booktitle={Proceedings of the 1993 ASME International Electronic Packaging Conference}, author={Eischen, J.W. and Reagan, S.}, year={1993} }
 @inproceedings{eischen_kim_1993, title={Optimization of Fabric Manipulation During Pick/Place Operations}, booktitle={Proceedings of the 4th Annual Academic Apparel Research Conference}, author={Eischen, J.W. and Kim, Y.}, year={1993} }
 @article{eischen_kim_1993, title={Optimization of Fabric Manipulation during Pick/Place Operations}, volume={5}, ISSN={0955-6222}, url={http://dx.doi.org/10.1108/eb003021}, DOI={10.1108/eb003021}, abstractNote={Uses a general large displacement beam theory to formulate a finite element‐based numerical method for simulating fabric drape, manipulation and contact. Presents numerical results corresponding to real fabric materials. Shows a broad class of fabric mechanics problems including how these effects can be solved.}, number={3/4}, journal={International Journal of Clothing Science and Technology}, publisher={Emerald}, author={Eischen, J.W. and Kim, Y.G.}, year={1993}, month={Mar}, pages={68–76} }
 @inproceedings{eischen_mcdevitt_1993, title={Simulation of Fabric Draping and Manipulation with Arbitrary Contact Surfaces and Adaptive Meshing}, booktitle={Proceedings of the 4th Annual Academic Apparel Research Conference}, author={Eischen, J.W. and McDevitt, T.}, year={1993} }
 @inproceedings{eischen_kim_1992, title={Fabric Mechanics Analysis Using Large Deformation Shell Theory}, booktitle={Proceeding of the 3rd Annual Academic Apparel Research Conference}, author={Eischen, J.W. and Kim, J.H.}, year={1992}, month={Feb} }
 @article{eischen_silverberg_wang_1992, title={Slewing Motion Control of a Very Flexible Elastic Beam}, volume={59}, ISSN={0021-8936 1528-9036}, url={http://dx.doi.org/10.1115/1.2893782}, DOI={10.1115/1.2893782}, abstractNote={Technical Briefs Slewing Motion Control of a Very Flexible Elastic Beam J. W. Eischen, J. W. Eischen Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910 Search for other works by this author on: This Site PubMed Google Scholar L. Silverberg, L. Silverberg Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910 Search for other works by this author on: This Site PubMed Google Scholar H. L. Wang H. L. Wang Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910 Search for other works by this author on: This Site PubMed Google Scholar Author and Article Information J. W. Eischen Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910 L. Silverberg Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910 H. L. Wang Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910 J. Appl. Mech. Sep 1992, 59(3): 684-687 (4 pages) https://doi.org/10.1115/1.2893782 Published Online: September 1, 1992 Article history Received: November 20, 1990 Revised: April 30, 1991 Online: March 31, 2008}, number={3}, journal={Journal of Applied Mechanics}, publisher={ASME International}, author={Eischen, J. W. and Silverberg, L. and Wang, H. L.}, year={1992}, month={Sep}, pages={684–687} }
 @inproceedings{ross_eischen_bayan_1992, title={The Problem of Helicopter and Aircraft Wire Strike Accidents}, booktitle={Proceedings of the 4th International Conference on Structural Failure, Product Liability and Technical Insurance}, author={Ross, B. and Eischen, J.W. and Bayan, F.}, year={1992} }
 @inproceedings{eischen_hisham_1991, title={Effect of Geometric Nonlinearities on Crack Tip Deformations}, booktitle={Proceedings of the Pan American Congress of Applied Mechanics}, author={Eischen, J.W. and Hisham, H.}, year={1991}, month={Jan} }
 @inproceedings{eischen_wetter_1991, place={Atlanta, GA}, title={Free Edge Stress Singularities in Electronic Bimaterials- Nonlinear Material Response}, booktitle={Proceedings of the Symposium on Structural Analysis in Microelectronics}, author={Eischen, J.W. and Wetter, C.H.}, year={1991} }
 @article{eischen_chung_1991, title={The Singularity at an Interface Between Bilinear Materials}, volume={28}, number={1}, journal={International Journal of Solids and Structures}, author={Eischen, J.W. and Chung, C.}, year={1991} }
 @inproceedings{eischen_kim_clapp_ghosh_1990, title={Computer Simulation of the Large Motions of Fabric Structures}, booktitle={Proceedings of the XV Southeastern Conference on Theoretical and Applied Mechanics}, author={Eischen, J.W. and Kim, Y.G. and Clapp, T.G. and Ghosh, T.}, year={1990} }
 @article{clapp_peng_ghosh_eischen_1990, title={Indirect Measurement of the Moment-Curvature Relationship for Fabrics}, volume={60}, ISSN={0040-5175 1746-7748}, url={http://dx.doi.org/10.1177/004051759006000906}, DOI={10.1177/004051759006000906}, abstractNote={ An indirect method of experimentally measuring the moment-curvature relationship for fabrics is developed in this study. The new test method involves recording the deformed coordinates of a fabric sample as it is cantilevered under its own weight from a fixed support. By applying least squares polynomial regression and numerical differentiation techniques, the coordinate data along with the values of fabric weight per unit area are used to construct the moment-curvature relationship of the fabric. This method and its associated computer algorithm have been validated by numerical simulations and experimental observations. The nonlinear moment-curvature rela tionship was used to approximate the nonlinear bending stiffness in fabrics. The ad vantage of this method is that the fabric nonlinear bending behavior, which is inherent in most fabrics, can be well represented; this property may not always be obtained from the traditional cantilever beam test. }, number={9}, journal={Textile Research Journal}, publisher={SAGE Publications}, author={Clapp, T.G. and Peng, H. and Ghosh, T.K. and Eischen, J.W.}, year={1990}, month={Sep}, pages={525–533} }
 @inproceedings{eischen_sun_marler_1990, series={ASME Book}, title={Multi-Rigid-Body Kinematic Analysis with Elastic Finite Elements}, volume={II}, booktitle={Proceedings of the 1990 ASME International Computers in Engineering Conference}, author={Eischen, J.W. and Sun, H. and Marler, M.}, year={1990}, collection={ASME Book} }
 @article{eischen_chung_kim_1990, title={Realistic Modeling of Edge Effect Stresses in Bimaterial Elements}, volume={112}, ISSN={1043-7398 1528-9044}, url={http://dx.doi.org/10.1115/1.2904333}, DOI={10.1115/1.2904333}, abstractNote={A classic paper by Timoshenko in 1925 dealt with thermal stresses in bimetal thermostats and has been widely used for designing laminated structures, and in contemporary studies of stresses in electronic devices. Timoshenko’s analysis, which is based on strength of materials theory, is unable to predict the distribution of the interfacial shear and normal stresses known to exist based on more sophisticated analyses involving the theory of elasticity (Bogy (1970) and Hess (1969)). Suhir (1986) has recently provided a very insightful approximate method whereby these interfacial stresses are estimated by simple closed-form formulas. The purpose of the present paper is to compare three independent methods of predicting the interfacial normal and shear stresses in bimaterial strips subjected to thermal loading. These are: 1.) Theory of elasticity via an eigenfunction expansion approach proposed by Hess, 2.) Extended strength of materials theory proposed by Suhir, 3.) Finite element stress analysis. Two material configurations which figure prominently in the electronics area have been studied. These are the molydeneum/aluminum and aluminum/silicon material systems. It has been discovered that when the two layers are nearly the same thickness, the approximate methods adequately predict the peak values of the interfacial stresses but err in a fundamental manner in the prediction of the distribution of stress. This may not be of concern to designers who are interested mainly in maximum stress alone. However, it has been shown that if one layer is relatively thin compared to the other, the approximate methods have difficulty in predicting both the peak value of stress and its associated distribution.}, number={1}, journal={Journal of Electronic Packaging}, publisher={ASME International}, author={Eischen, J. W. and Chung, C. and Kim, J. H.}, year={1990}, month={Mar}, pages={16–23} }
 @inproceedings{eischen_1989, title={Geometric Non-linearity in a Bi-Material Strip}, booktitle={Proceedings of the International Congress of Applied Mechanics}, author={Eischen, J.W.}, year={1989}, month={Aug} }
 @inproceedings{eischen_sun_1989, title={Multi-Rigid-Body Kinematic Analysis with Elastic Finite Elements}, volume={15}, booktitle={Proceedings of the Symposium on Dynamics and Control of Multi-Body/Robotic Systems with Space Applications, ASME Dynamic Systems and Controls}, author={Eischen, J.W. and Sun, H.}, year={1989} }
 @article{eischen_everett_1989, title={Thermal Stress Analysis of a Bimaterial Strip Subject to an Axial Temperature Gradient}, volume={111}, ISSN={1043-7398 1528-9044}, url={http://dx.doi.org/10.1115/1.3226548}, DOI={10.1115/1.3226548}, abstractNote={Formulas are derived for the stresses and displacements in a bimaterial strip which is subjected to a temperature gradient that varies linearly in the longitudinal direction. The solution is obtained by superposing certain fundamental linear elastic stress states which are compatible with bar and beam theory. The analytical results are approximate in the sense that stress-free boundary conditions are not satisfied exactly, since only zero resultant force and moment conditions are enforced. Finite element calculations have been performed to verify the results and to ascertain the level of stress concentration near the ends of the strip.}, number={4}, journal={Journal of Electronic Packaging}, publisher={ASME International}, author={Eischen, J. W. and Everett, J. S.}, year={1989}, month={Dec}, pages={282–288} }
 @book{everett_eischen_1988, title={Deformation and Stress in Thin BiMaterial Elements with an Axial Temperature Variation}, number={88- WA/EEP-15}, author={Everett, J.S. and Eischen, J.W.}, year={1988} }
 @article{eischen_1987, title={An improved method for computing the integral}, volume={26}, ISSN={0013-7944}, url={http://dx.doi.org/10.1016/0013-7944(87)90134-2}, DOI={10.1016/0013-7944(87)90134-2}, abstractNote={The J2 integral, used in conjunction with the well-known J (or J1) integral, can assist the analyst in the prediction of in-plane mixed-mode stress intensity factors via finite element stress analysis. However, direct evaluation of J2 yields results which are very sensitive to the crack tip modeling employed, thus reducing the efficacy of the J2 integral. A new technique is proposed to circumvent this problem. This new technique also permits one to easily calculate the non-singular stress component σx0 which is known to be important in predicting crack kinking angles.}, number={5}, journal={Engineering Fracture Mechanics}, publisher={Elsevier BV}, author={Eischen, J.W.}, year={1987}, month={Jan}, pages={691–700} }
 @article{eischen_herrmann_1987, title={Energy Release Rates and Related Balance Laws in Linear Elastic Defect Mechanics}, volume={54}, ISSN={0021-8936 1528-9036}, url={http://dx.doi.org/10.1115/1.3173024}, DOI={10.1115/1.3173024}, abstractNote={A simple and direct derivation of certain balance (or conservation) laws for linear dynamic elasticity is presented including nonhomogeneities, thermal effects, anisotropy, and body forces. Additionally, the connection between the balance laws and energy release rates for defect motions is established.}, number={2}, journal={Journal of Applied Mechanics}, publisher={ASME International}, author={Eischen, J. W. and Herrmann, G.}, year={1987}, month={Jun}, pages={388–392} }
 @article{eischen_1987, title={Fracture of Non-homogeneous Materials}, volume={34}, number={3}, journal={International Journal of Fracture}, author={Eischen, J.W.}, year={1987} }
 @article{eischen_1987, title={Fracture of Nonhomogeneous Materials}, url={https://doi.org/10.1007/BF00042121}, DOI={10.1007/BF00042121}, journal={International Journal of fracture}, author={Eischen, Jeffrey}, year={1987} }
 @article{sosa_eischen_1986, title={Computation of stress intensity factors for plate bending via a path-independent integral}, volume={25}, ISSN={0013-7944}, url={http://dx.doi.org/10.1016/0013-7944(86)90259-6}, DOI={10.1016/0013-7944(86)90259-6}, abstractNote={A simple and accurate method to determine stress intensity factors in cracked plates subjected to bending loads is proposed. A new vectorJ denned in terms of the sum of line and domain integrals is derived and expressed in terms of plate resultant quantities through the use of Reissner's transverse shear theory. Mindlin's plate theory is also treated within this framework. Of particular interest is the accomodation of the effect of a distributed pressure load. Relationships between J and the stress intensity factors are presented and employed for solving several example problems with the aid of finite element analysis. Detailed modeling of the crack tip region is completely avoided with this formulation. The stress intensity factor is computed for the case of a square plate containing a through crack and subjected to uniform transverse pressure loading. The geometric boundary conditions and Poisson's ratio were treated as parameters in this analysis.}, number={4}, journal={Engineering Fracture Mechanics}, publisher={Elsevier BV}, author={Sosa, Horacio A. and Eischen, Jeffrey W.}, year={1986}, month={Jan}, pages={451–462} }
 @article{duan_eischen_herrmann_1986, title={Harmonic Wave Propagation in Nonhomogeneous Layered Composites}, volume={53}, ISSN={0021-8936 1528-9036}, url={http://dx.doi.org/10.1115/1.3171694}, DOI={10.1115/1.3171694}, abstractNote={A new method for analyzing plane wave propagation in a periodically layered, elastic, nonhomogeneous composite body is proposed. The nonhomogeneity considered is a variation of the material properties within each composite layer. Results from probability theory are used to arrive at the two fundamental solutions of the governing second order ordinary differential equations. Floquet’s wave theory is combined with a Wronskian formula to yield the dispersion relationship for this nonhomogeneous composite. Numerical results show that the presence of material nonhomogeneity affects the range of frequencies which can pass through the composite unattenuated.}, number={1}, journal={Journal of Applied Mechanics}, publisher={ASME International}, author={Duan, Z. P. and Eischen, J. W. and Herrmann, G.}, year={1986}, month={Mar}, pages={108–115} }