TY - JOUR
TI - High strain-rate localization and failure of crystalline materials
AU - Zikry, M.A.
AU - Nemat-Nasser, S.
T2 - Mechanics of Materials
AB - A theoretical and a computational model are introduced to study the micromechanical high strain-rate failure mechanisms of shear-strain localization in monocrystalline fcc structures. A theoretical framework for a constitutive model for the dynamic finite plastic deformation of rate-dependent single fcc crystals is developed. The micromechanics of plastic flow are based on a high strain-rate single crystal plasticity model and a visco-plastic power law. The single crystal is subjected to far-field dynamic tensile strain-rates ranging from 100/s to 2000/s. An explicit finite-element model is introduced for the integration of the numerically stiff visco-plastic constitutive relations. The total deformation rate tensor is obtained by the central difference explicit integration of the equations of motion. The plastic deformation rate tensor is obtained from the solution of an initial-value nonlinear problem for the resolved shear stresses. In time intervals when the differential equations for the resolved shear stresses are not numerically stiff, the initial-value problem is integrated by the explicit fifth-order Runge-Kutta adaptive time-step method. In time domains where the propagated error grows and the time-step must be restricted due to stability requirements, which is an indication of numerical stiffness, the initial-value problem is integrated by an A-stable method. To correctly differentiate time-step reductions due to stability, from time-step reductions due to accuracy, a stiffness ratio is defined. The present analysis corroborates experimental observations that high strain-rate shear-strain localization, in rate-dependent crystals, is a function of thermal and geometrical softening, overall strain-rates, strain hardening, strain-rate hardening, and strain-rate sensitivity.
DA - 1990///
PY - 1990///
DO - 10.1016/0167-6636(90)90044-G
VL - 10
IS - 3
SP - 215-237
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0025640233&partnerID=MN8TOARS
ER -
TY - CONF
TI - Multi-Rigid-Body Kinematic Analysis with Elastic Finite Elements
AU - Eischen, J.W.
AU - Sun, H.
AU - Marler, M.
T2 - 1990 ASME International Computers in Engineering Conference
T3 - ASME Book
C2 - 1990///
C3 - Proceedings of the 1990 ASME International Computers in Engineering Conference
DA - 1990///
PY - 1990///
VL - II
ER -
TY - CONF
TI - Computer Simulation of the Large Motions of Fabric Structures
AU - Eischen, J.W.
AU - Kim, Y.G.
AU - Clapp, T.G.
AU - Ghosh, T.
T2 - XV Southeastern Conference on Theoretical and Applied Mechanics
C2 - 1990///
C3 - Proceedings of the XV Southeastern Conference on Theoretical and Applied Mechanics
CY - Atlanta, GA
DA - 1990///
PY - 1990///
ER -
TY - BOOK
TI - Welding of Plastics
AU - Rabiei, A.
DA - 1990///
PY - 1990///
PB - Shahrab Publishers
ER -
TY - JOUR
TI - Realistic Modeling of Edge Effect Stresses in Bimaterial Elements
AU - Eischen, J. W.
AU - Chung, C.
AU - Kim, J. H.
T2 - Journal of Electronic Packaging
AB - 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. Timoshenkoâ€™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.
DA - 1990/3/1/
PY - 1990/3/1/
DO - 10.1115/1.2904333
VL - 112
IS - 1
SP - 16-23
LA - en
OP -
SN - 1043-7398 1528-9044
UR - http://dx.doi.org/10.1115/1.2904333
DB - Crossref
ER -
TY - JOUR
TI - Indirect Measurement of the Moment-Curvature Relationship for Fabrics
AU - Clapp, T.G.
AU - Peng, H.
AU - Ghosh, T.K.
AU - Eischen, J.W.
T2 - Textile Research Journal
AB - 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.
DA - 1990/9//
PY - 1990/9//
DO - 10.1177/004051759006000906
VL - 60
IS - 9
SP - 525-533
J2 - Textile Research Journal
LA - en
OP -
SN - 0040-5175 1746-7748
UR - http://dx.doi.org/10.1177/004051759006000906
DB - Crossref
ER -
TY - CONF
TI - Controllability and stabilizability properties of a nonholonomic control system
AU - Bloch, A.M.
AU - Reyhanoglu, M.
T2 - 29th IEEE Conference on Decision and Control
AB - Controllability and stabilizability properties are examined for a control system with a nonholonomic constraint. A representative nonholonomic control system example is discussed: the control of a knife edge moving on a plane surface. This example contains the essential features of the general case. It is noted that conditions for small-time local controllability are satisfied. An explicit open loop control is then given which transfers the knife edge to a single equilibrium and an explicit stabilizing feedback control.< >
C2 - 1990///
C3 - 29th IEEE Conference on Decision and Control
DA - 1990///
DO - 10.1109/cdc.1990.203820
PB - IEEE
UR - http://dx.doi.org/10.1109/cdc.1990.203820
DB - Crossref
ER -