PERIDYNAMIC UNIT CELL ENABLED FINITE ELEMENT MODELING OF FIBER STEERED COMPOSITES

This study presents an approach based on traditional finite elements and peridynamic unit cell (PDUC) to perform structural analysis of fiber steered composite laminates. Effective material property matrix for each ply in the plate element is computed by employing the PDUC based on the orientation of the fiber path and orthotropic ply properties. Each element defines the unit cell domain if the element shape is rectangular. Otherwise, the rectangle that circumscribes the element defines the domain of the unit cell. The element stiffness matrix is constructed through a traditional finite element implementation. This approach provides an accurate and simple modeling of variable angle tow laminates. It can be readily integrated in commercially available finite element programs.

Prediction of Effective Material Property of Tailor Welded Blanks for Air Bending Process

A method based on artificial neural network (ANN) for predicting the effective material property is put forward in this paper. The finite element model of tensile test specimen is modeled in LS-DYNA code, which has transverse weld at the middle of the specimen and conforms to the ASTM specification. A statistical error analysis model is used to include the random phenomenon in the result of tensile test finite element model and verify the accuracy of finite element model (FEM) simulation. In order to study the effect of the processing parameter with design of experiment is followed, the simulation trail is conducted in all the levels of parameters. It is assumed that Hollomon’s law is followed by tailor welded blanks. The results obtained from fitting the post-process data of FEM by least square method are used to train and develop ANN model, the prediction average error of ANN model is acceptable compared with simulation trail.

A Methodology for Evaluating the Variability in Fracture Properties of Ferritic Nuclear Pressure Vessel Steels

A methodology is presented upon which an effective material property design curve can be based. The methodology is a statistically developed procedure which allows appropriate confidence limits to be established. The application of this methodology is a goal of a recently completed fracture toughness program of the Electric Power Research Institute (EPRI), and the results of this program are presented in this paper. The methodology is designed to allow the formulation of a statistically based KIR (reference toughness) curve as contrasted with the present approach which is found in Appendix G, Section III, of the ASME Boiler and Pressure Vessel Code.