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• Users Manual for LS-DYNA Concrete Material Model 159

Users Manual for LS-DYNA Concrete Material Model 159

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Chapter 1. Introduction

The goal of the work performed under this program, entitled Development of DYNA3D Analysis Tools for Roadside Safety Applications II, is to develop a concrete material model for use in roadside safety simulations, implement the model into the LS-DYNA finite element code, and evaluate the model against available test data. Material models for wood and soil were developed previously for a similar program entitled Development of DYNA3D Analysis Tools for Roadside Safety Application (1998-2002).

This report documents the concrete model theory, reviews the LS-DYNA model input, and provides example problems for use as a learning tool. A companion report, entitled Evaluation of the LS-DYNA Concrete Model 159 thoroughly documents the concrete model evaluation calculations.⁽¹⁾ Users manuals and evaluation reports are also available for the wood and soil material models. (See references 2, 3, 4, and 5.)

This manual is divided into three main chapters. Chapter 2, "Theoretical Manual," begins with a general description of concrete behavior, and then provides a detailed theoretical description of the model as implemented in LS-DYNA version 971. This chapter contains equations for all formulations implemented, including:

• Isotropic constitutive equations.
• Three stress-invariant shear surface with translation for prepeak hardening.
• A hardening cap that expands and contracts.
• Damage-based softening with erosion.
• Rate effects for high strain rate applications.

The concrete model includes initialization routines that provide the user with default input parameters for normal strength concrete (with compressive strengths between about 28 and 58 megapascals (MPa) (4,061 and 8,412 pounds per square inch (psi))). These initialization routines set the required strengths, stiffnesses, hardening, softening, and rate effects parameters as a function of concrete compressive strength and maximum aggregate size. The Theoretical Manual describes all test data and assumptions used to set the default input parameters for concrete.

Chapter 3, "Users Manual," describes the concrete model input in LS-DYNA format. This chapter includes descriptions of all input parameters as well as a theoretical description of the model. The chapter is intended to be a manual for users who want to apply the model, without delving deeply into the theory of the model. Most information contained in this chapter is included in the LS-DYNA Keyword Users Manual.⁽⁶⁾

Chapter 4, "Examples Manual," provides input files and output plots for two single element simulations. These example problems are designed to help the user become familiar with applications of the concrete material model. Additional example problems are given in the companion to this report.⁽¹⁾

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