A Demonstration of the Method of Stochastic Finite Element Analysis
Abstract
Finite element analysis has been used as a design to ol for many years, with structural reliability being ensured through use of a liberal factor of safety. Unfortunately, the safety factor is a blanket insurance against all hazards, and a designer has no way to optimize a structure against any particular hazard. This is particularly troublesome in the fields of aero/astro design, where every bit of mass must serve to maximum utility. The method of Stochastic Finite Element Analysis allows a designer to model any loading or hazard condition as closely to reality as desired by using an appropriate probability distribution function. Through a Monte Carlo simulation, the finite element model is subject to the probability functions. The cumulative output is analyzed for trends in failure probability and the design is altered to enhance its reliability, repeating the process until the desired level of reliability is achieved. The resulting design is optimal for the imposed conditions, and compared to a structure designed with a traditional factor of safety approach, is either lighter or more reliable. This demonstration revealed that for similar reliabilities, a stochastically designed wing was 20% lighter than a wing strengthened by the factor of safety. The major drawback in applying the method of stochastic finite element analysis is that very large, complex models can require extraordinary amounts of computer resources. Keywords: These, ASTROS computer program, ASTROS(automated structural optimization system).
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1989
- Accession Number
- ADA206135
Entities
People
- Paul R. Bryant
Organizations
- Air Force Institute of Technology