Optimized Shape Design Of Truss Structure With Reliability Constraint

The traditional structure optimization design accords to deterministic designthought. Considering the uncertainty in actual engineering, we should introduce thetheory of structural reliability structure optimization design, to ensure the reliability ofthe optimized scheme, and this is also a common difficulty in structural optimization.The past structure optimization design is based on reliability. Most people just stay inthe plane size optimization, and few people combine reliability constraints, sizeoptimization and shape optimization. Relative to the size optimization, the shapeoptimization is much higher difficulty. And combining reliability constraints, sizeoptimization and shape optimization will make problems become more complicated.This article is challenging research work.Because of the size and shape optimization design variables of values in a differentway, and to the objective function and constraint function the influence degree isdifferent. If the two kinds of design variables directly optimized at the same time, oftencausing optimized algorithm is difficult to convergence. In this paper two types ofdesign variables separation, two types of alternating iterative optimization design andthe reliability constraints into size optimization, making the resulting optimization underthe condition of satisfy the constraint conditions with the lowest cost.In this paper, the optimization algorithm is composed of two sub branch. The firstis the size optimization based on reliability of truss structure. This article using methodis to introduce fmincon optimization function of matlab. The traditional method of toothrow is improved. Replacing the traditional tooth row with fmincon functionoptimization method of full stress step, and making the optimization results moreaccurate. And good reliability constraints can be integrated into the size optimizationmodel to form a new improved method of tooth row. This method is efficiency andprecision is high. The second is the shape of the truss structure optimization. Due to thestructural shape optimization started relatively late and difficult. So far, it hasn’t formedthe structure of the classic shape optimization method. The most commonly usedstructural shape optimization is to use a derivative sensitivity and to calculate thesensitivity, and then through the sensitivity to search out the optimal results. But directlyuse the derivation of the method to calculate sensitivity, the amount of calculation is toolarge. Especially at the time of design variables is much. Often computation efficiencyis not high. This article uses the relative direction difference quotient instead sensitivityfor searching the optimal results. Not only ensure the precision of the calculation results, and the optimization efficiency is significantly increased. Two child division willalternat iteration,until meeting the convergence criteria,to get the final optimizationresults.At the end of the article,using the method of actual project optimize,and verifythe effectiveness of this method in practical application.