@article{tan_matzen_yu_2002, title={Correlation of test and FEA results for the nonlinear behavior of straight pipes and elbows}, volume={124}, ISSN={["1528-8978"]}, DOI={10.1115/1.1493806}, abstractNote={This paper summarizes the literature on reconciliation of finite element analyses with in-plane bending experiments on piping elbows. It then describes in detail two four-point-bending tests on straight pipes and two in-plane bending tests on elbows and the corresponding nonlinear finite element analyses. Using a new procedure for obtaining a stress-strain curve for stainless steel using only values for E,Sy, and Su and a representative stress-strain curve from a test on a similar material specimen, the nonlinear responses of the piping components tested are shown to be simulated more accurately than previously published results.}, number={4}, journal={JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME}, author={Tan, Y and Matzen, VC and Yu, LX}, year={2002}, month={Nov}, pages={465–475} }
 @article{yu_matzen_1999, title={B-2 stress index for elbow analysis}, volume={192}, ISSN={["0029-5493"]}, DOI={10.1016/S0029-5493(99)00112-0}, abstractNote={The purpose of this study is to evaluate the effect of end constraint, geometric dimension and internal pressure on the B2 stress indices, and thus to determine the conservativeness of the code equation for B2 stress indices. For a series of stainless steel elbow-straight pipe connections of different sizes and schedules, with flanges attached at different locations and with different levels of applied internal pressure, nonlinear finite element analyses were performed considering both material and geometrical nonlinearities. Load-deflection curves were obtained, and from these curves, collapse limit loads were determined. B2 stress indices were computed using the equation B2=Sy/(Mcl/Z). The B2 stress indices of elbows with flanges attached at different locations were compared. Also compared were B2 stress indices of elbows with different levels of internal pressure. Finally the B2 stress indices from the finite element analysis are compared with the B2 stress indices computed from code equation. Regression analysis is used to determine revised numerical values for the code equation for B2. A new, less conservative equation is proposed to be used to compute B2 stress indices for elbow component.}, number={2-3}, journal={NUCLEAR ENGINEERING AND DESIGN}, author={Yu, LX and Matzen, VC}, year={1999}, month={Sep}, pages={261–270} }
 @article{matzen_yu_1998, title={Elbow stress indices using finite element analysis}, volume={181}, ISSN={["0029-5493"]}, DOI={10.1016/S0029-5493(97)00352-X}, abstractNote={Existing ASME Code provisions allow for an experimentally determined collapse load. This collapse (limit) load can then be used in the Code equation defining stress indices to obtain a stress index experimentally. This paper describes a research project to investigate the use of inelastic finite element analysis, rather than experiments, to obtain the collapse load. An example is given for a 2-in., schedule 40, long radius, 90°, stainless steel elbow with 10-in.-long straight pipes on each end. A B2 index is found using this approach which is nearly 50% lower than the one obtained using the Code equation for B2.}, number={1-3}, journal={NUCLEAR ENGINEERING AND DESIGN}, author={Matzen, VC and Yu, LX}, year={1998}, month={May}, pages={257–265} }