【Technical articles】Impact Analysis featuring Ansys LS-DYNA

Introduction

Computer-Aided Engineering (CAE) has been synonymous with Structural Analysis since the dawn of computer simulation. With the introduction of Explicit Dynamics, more and more windows of opportunity have been open. Phenomena that happened in a very short period of time (we are talking about few milliseconds or even microseconds here), can be simulate. For example, an Impact Test for a Reinforced Concrete Beam.

Reinforced concrete (RC) is a composite material in which reinforcement with higher tensile strength or ductility counteracts the comparatively low tensile strength and ductility of the concrete. Typically, but not always, the reinforcement is steel reinforcing bars (rebar), and is generally passively inserted in the concrete until the concrete sets. The type of steels or materials used for the rebar depending on the size, shapes and function of the concrete.

In the design and development of concretes for construction, several different types of tests are conducted to evaluates its compressive strength, shear strength, flexural strength and so on. Some of those tests include bending test, compression test, and also impact test. One of the problems about material testing, although it puts out an accurate result, it can be time consuming and costly.

On the other hand, a virtual test on a computer using CAE can eliminate those problems. With CAE, it is possible to produce results in about a matter of hours if not minutes per case. This makes it possible to simulate and evaluate multiple shapes, size, and material used for the structure. It allows the user to simulate under different conditions without a physical prototype, and quickly derive the optimum structure at a relatively low cost.

LS-DYNA has been the class-leading software for Explicit Dynamics and other type of analysis. With the availability of LS-DYNA solver capabilities within ANSYS Workbench Mechanical environment, the users can have the powerful LS-DYNA solver to work with, and the convenience and ease-of-use simulation environment provided by ANSYS. LS-DYNA also rich with different type of material model to choose from, making it highly flexible for the users to do any type of simulation.
In this article, we will introduce an example of Impact Analysis of two different concrete beams using ANSYS LS-DYNA.

Purpose of Analysis

To study the difference in damage imposed and structural integrity of two different concrete beams, non-reinforced and reinforced concrete beam.

Figure. Strain contour and fracture behaviour of the Reinforced Concrete Beam