Damage constitutive models based on micromechanical formulation and a combination of micromechanical and macromechanical effects were developed by the authors to predict progressive damage in aligned and randomly oriented carbon fiber polymer composites. The models are extended in order to account for the microcrack effect on the mechanical behavior of the composites. Progressive interfacial fi...

This paper presents a detailed workload characterization of important technical and JavaTM applications used in the industry, on the Itanium2 processor. We present a detailed performance study of four major classes of technical applications: 1Crash finite element analysis (LS-Dyna3D). 2Structural analysis (Nastran). 3Computational fluid dynamics (Star-CD). 4Other technical applications (GUPS). ...

Prototype guardrails, bridge rails, crash cushions and other roadside safety hardware have been designed in part by using engineering judgment, experience and intuition. These prototypes have been later evaluated by performing full-scale crash tests representing expected worst case scenarios. Since these tests are relatively expensive and because they require specialized facilities and personne...

The objective of this research is to develop a new methodology with software tools for the joint design of an advanced composite armor (ACA) under ballistic impact and other loading conditions. An innovative design methodology, topology optimization, is extended for the composite armor joint design problem. This includes ballistic impact analyses of the ACA, function analyses and targets settin...

Damage constitutive models based on micromechanical formulation and combination of micromechanical and macromechanical effects are presented to predict progressive damage in aligned and random fiber reinforced composites. To estimate the overall elastoplastic damage responses, an effective yield criterion is derived based on the ensemble-volume averaging process and the first-order effects of e...

Complex nature of the fibre reinforced composites, their non-homogeneity and anisotropy make modelling a challenging task. Although linear – elastic behaviour composites is well understood, there still significant uncertainty regarding prediction damage initiation, evolution material failure especially for general loading case characterised with triaxial state stress or strain. Consequently, si...

This paper describes simulation studies using the public domain version of the DYNA3D hydrocode of the torsion test, which by definition is a 3 dimensional test. The mesh resolution required to resolve the stress system and the general shear deformation within the gauge length of the specimen has been investigated. Furthermore the simulations have been compared in detail with experiments in ter...

Highway and roadside safety features are crash tested for compliance with certain safety criteria. US Federal Highway Administration (FHWA) uses a surrogate reusable test vehicle, Bogie, to conduct crash tests of roadside safety features. Bogie is intended to replace an impacting vehicle in order to reduce the cost of the test. Bogie can be configured with different crushable impact noses repre...

This work compares the relative importance of material anisotropy in sheet forming as compared to other material and process variables. The comparison is made quantitative by the use of normalized dependencies of depth to failure (forming limit is reached) on various measures of anisotropy, as well as strain and rate sensitivity, friition, and tooling. Comparisons are made for a variety of form...