Reliability design of structures
Chan, Craig Wen Ning
Date of Issue2018
School of Mechanical and Aerospace Engineering
The Reliability Design Method is an increasingly popular method of analysis in the engineering world. Also known as probabilistic design, it uses statistical methods to determine a structure’s probability of failure which aids in reducing production costs and improving structural design. Using the traditional method of deterministic analysis, the analysis of simple structures such as a truss structure or cantilever beam is relatively simple when there is knowledge of their shape and form. However, in today’s world, most structures have complex shapes and forms which makes it extremely difficult for deterministic analysis. This leads to conservative assumptions commonly expressed as the safety factor and this often results in an over-designed structure. Reliability-based analysis uses a finite element calculation model to analyze complex structures and with the increasing complexity of structures, computer aided engineering software are used to assist in the analysis. The objective of this project is to introduce and review the methodologies that encompasses the probabilistic analysis of two chosen structures with the use of ANSYS. ANSYS can analyze and identify the high stress regions in a structure under different loading conditions and this allows the probability of failure of the structure to be determined. This is achieved assuming probability distributions for the random input variables, such as material properties and applied loading, before using the Monte Carlo Simulation to determine the probability of failure over a selected number of samples. In this report, the two model structures chosen to illustrate the concepts of structural reliability are a bracket and a domestic gasoline cylinder. It is intended to use these examples to illustrate the precision, efficiency and effectiveness of the reliabilitybased method using ANSYS.
Final Year Project (FYP)
Nanyang Technological University