Implementation and validation of a three-dimensional plasticity-based deformation model for orthotropic composites

Verification and Validation of a Three-Dimensional Orthotropic Plasticity Constitutive Model Using a Unidirectional Composite

“…The input to the model consists of 12 tabulated stress-strain curves generated from actual experimental or virtual tests [10]-1, 2 and 3-direction tension curves, 1, 2 and 3-direction compression curves, 1-2, 2-3 and 3-1 plane shear curves, and 45 • off-axis tension/compression curves in the 1-2, 2-3 and 3-1 planes. A brief summary of the deformation model is presented here and further details can be found in our earlier publications [11][12][13]. The yield function is a modified form of the commonly used Tsai-Wu composite failure model and is defined as…”

“…An impact test (LVG905) was conducted at National Aeronautics and Space Administration's Glenn Research Center to validate the developed model [12]. The test involves a 30.48 cm × 30.48 cm × 0.3099 cm (12 in × 12 in × 0.122 in) thick composite flat panel subjected to a low velocity impact.…”

“…After the tests, the panels were carefully investigated and the examinations showed no damage and failure. In the current version of MAT213 implementation, (a) the deformation model requires 12 stressstrain curves for each set of temperatures and strain rates: 1, 2 and 3-direction tension curves, 1, 2 and 3-direction compression curves, 1-2, 2-3 and 3-1 plane shear curves, and 45° off-axis tension/compression curves in the 1-2, 2-3 and 3-1 planes [10][11][12]; (b) the damage model requires kl ij d versus total strain curves [18,19]; and (c) a simple failure model (principal strain theory) is currently implemented with the intent to flag models where one or more strain components has exceeded limiting values, rather than to actually predict failure. For the impact test under consideration, quasistatic, room temperature data was used.…”

“…The aluminum impactor was modeled with 27,200 8-noded hexahedral elements. The aluminum impactor was modeled using a piecewise linear plasticity model (MAT24) with the material properties given in [12]. No damping parameters were used in the FE models.…”

“…Others require additional parameters to characterize failure using classical failure theories at the macroscopic level, e.g., Chang-Chang or Tsai-Wu, or a mixture of macroscopic level and local (fiber/matrix) driven failure, e.g., Hashin. This type of approach leads either to models with only a few parameters, which provide a crude approximation at best to the actual stress-strain curve, or to models with many parameters which require a large number of complex tests to characterize [12]. Often, the lack of flexibility or sophistication in these models require that designers adjust the values of some of the model parameters using data from full-scale structural tests.…”