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Sensitivity analysis of the non-linear dynamic viscoplastic response of 2-d structures with respect to material parametersA computational procedure is presented for evaluating the sensitivity coefficients of the viscoplastic response of structures subjected to dynamic loading. A state of plane stress is assumed to exist in the structure, a velocity strain-Cauchy stress formulation is used, and the geometric non-linearities arising from large strains are incorporated. The Jaumann rate is used as a frame indifferent stress rate. The material model is chosen to be isothermal viscoplasticity, and an associated flow rule is used with a von Mises effective stress. The equations of motion emanating from a finite element semi-discretization are integrated using an explicit central difference scheme with an implicit stress update. The sensitivity coefficients are evaluated using a direct differentiation approach. Since the domain of integration is the current configuration, the sensitivity coefficients of the spatial derivatives of the shape functions must be included. Numerical results are presented for a thin plate with a central cutout subjected to an in-plane compressive loading. The sensitivity coefficients are generated by evaluating the derivatives of the response quantities with respect to Young's modulus, and two of the material parameters characterizing the viscoplastic response. Time histories of the response and sensitivity coefficients, and spatial distributions at selected times are presented.
Document ID
19950019846
Acquisition Source
Legacy CDMS
Document Type
Other
Authors
Kulkarni, Makarand
(Virginia Univ. Hampton, VA, United States)
Noor, Ahmed K.
(Virginia Univ. Hampton, VA, United States)
Date Acquired
September 6, 2013
Publication Date
April 1, 1995
Publication Information
Publication: Center for Computational Structures Technology
Subject Category
Structural Mechanics
Accession Number
95N26266
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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