Optimization Using Nimrod/O and Its Application to Robust Mechanical Design

Abstract

We describe the Nimrod/O distributed optimization tool and its application to a problem in mechanical design. The problem is to determine the shape for a hole in a thin plate under load that gives optimal life in the presence of flaws. The experiment reveals two distinct design strategies for optimizing this life. Nimrod/O is able to find both of these rapidly due to its inherent parallelism.

Robust workflows for science and engineering

“…Nimrod/O generates jobs in parallel batches, using parallel versions of various search algorithms where possible [1][23] [24]. Nimrod/O also executes multiple searches concurrently in order to handle non-linear problems that have multiple local minima.…”

An Evolutionary Programming Algorithm for Automatic Engineering Design

“…Finite element analysis of a thin plate under cyclic loading, with a cutout specified by parameters, was used to generate the Crack datasets [11]. Common practice in damage tolerant design has been to minimise the maximum stress under load.…”

Model Optimization and Parameter Estimation with Nimrod/O

“…This work [16], modelled the fatigue life of plates containing an access hole, as occurs for example in stiffeners in airplane wings. This required finite element computation of the stress field and the Paris model of the growth of pre-existing cracks.…”

“…This is normally cheaper, allows exploration of a wider range of scenarios and the possibility of optimization of the design. Consider for example a design problem in mechanical engineering, that of choosing the shape of a component that meets the functional specifications and is also optimal in the sense of giving maximal fatigue life [16]. Computation of the fatigue life involves a finite element analysis of the stress field followed by computation of perturbations produced by a range of hypothetical pre-existing cracks and calculation of the growth rate of these cracks under a given load regime.…”