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MSC Software Corporation is a software company based in Newport Beach, California, that specializes in simulation software. Wikipedia.

Gu P.,MSC Software | Dao M.,Massachusetts Institute of Technology
Applied Physics Letters

This paper discusses three aspects that have not been looked into within mechanistic model for rationalizing observed behavior of nanocrystalline materials. (1) For the nano-materials with low energy barrier to emit the trailing partial after the leading partial, such as nanocrystalline Al (nc-Al), both partials extend intra-granularly in strengthening effect. (2) In the transition grain-size region between strengthening and softening, the coupled effect of intra-granular dislocation extension and grain boundary deformation contributes to flow stress. (3) Reformulating the non-homogeneous nucleation model, the activation volume is further examined. © 2013 American Institute of Physics. Source

Gu P.,MSC Software | Dao M.,Massachusetts Institute of Technology | Asaro R.J.,University of California at San Diego | Suresh S.,Massachusetts Institute of Technology
Acta Materialia

We present a unified mechanistic model to rationalize size-dependent flow stress, activation volume and strain-rate sensitivity for metals with either nanocrystalline grains or nanoscale twins. The non-uniform partial dislocation model for flow stress [Asaro and Suresh, Acta Mater, Vol. 53, pp. 3369-3382, 2005; Gu et al., Scripta Mater, Vol. 62, pp. 361-364, 2010 is generalized here to consider both grain-size dependence and twin-thickness dependence of nanotwinned metals. A non-homogeneous nucleation model is proposed to predict the dependence of activation volume on both grain-size and twin-thickness. With the activation volume predicted from the non-homogeneous nucleation model and the flow stress obtained via the non-uniform partial dislocation model, strain-rate sensitivity as a function of characteristic structural length scale is also evaluated. This provides a unified approach from envisioning partial dislocation emission for the three size-dependent parameters characterizing the plastic deformation mechanism, flow stress, activation volume and strain-rate sensitivity, so that each one of these parameters is predicted when the geometry of the grains or nanotwins is known. The model predictions are shown to be consistent with a variety of available experimental data. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Source

Harvey S.M.,MSC Software
Journal of Materials Engineering and Performance

Nitinol self-expanding stents are used to treat peripheral occluded vessels such as the superficial femoral artery or the carotid. The complex vessel articulation requires a stent device that is flexible and kink resistant yet durable. The present study shows how the latest advances in commercially available engineering software tools permit engineering simulations of the many aspects of the Nitinol stent design and analysis. Two stent geometries are evaluated: a helical type stent design, and a more traditional straight strut, with multiple crowns design. The fatigue performance of the two stents is compared. The results show that advanced nonlinear finite element simulations and fatigue predictions of the Nitinol stent are possible today inside realistic simulated human arteries. The finite element analysis software used in this study is SimXpert, Marc, and Mentat (MSC Software, Santa Ana, CA). © ASM International. Source

Gu P.,MSC Software | Kad B.K.,University of California at San Diego | Dao M.,Massachusetts Institute of Technology
Scripta Materialia

The partial dislocation model for the deformation mechanism of nanocrystalline materials is extended to consider the influence of non-uniform dislocation extension. The non-uniform partial dislocation extension model is more consistent with experimental data than the original partial dislocation model. Additionally, the flow stress obtained from the non-uniform extension model is compared with that from the Hall-Petch relation. © 2009 Acta Materialia Inc. Source

Son J.,MSC Software | Lee H.-J.,Halcrow Inc.
Engineering Structures

Since the terrorist attacks of 2001, concern about potential car bomb attacks on buildings and infrastructure such as bridges and tunnels has increased tremendously. Design for better performance of these structures subjected to blast load is important to prevent progressive collapse of the structure and catastrophic loss of lives. The objective of this research was to study the performance of hollow steel box and concrete-filled composite pylons of a cable-stayed bridge subjected to blast loads. Car bomb detonation on the deck is assumed to be the most likely scenario to occur. A coupled numerical approach with combined Lagrangian and Eulerian models was used to consider the interaction of the deck and pylon with the air that transfers the explosion effect to the bridge. The non-linear explicit finite element analysis program, MD Nastran SOL700 was used to simulate the spatial and time variation of the blast load as well as blast shock wave-bridge interaction response. The blast resistance of two different types of pylons was investigated in a comparative study. The study established damage patterns of the pylon and showed superior performance of the concrete-filled composite pylon over the hollow steel box pylon. For the hollow steel box pylon, the P-δ effect on the instability of the pylon subjected to blast load was significant. © 2010 Elsevier Ltd. Source

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