Optimization Design Of Multi-cell Thin-walled Components With Crashworthiness Criterion

Motor vehic le traffic accident is a worldwide proble m, which serio us lyendanger people’s lives and hea lth, and it also caused serious damage to socia leconomy. Thus improve the crashworthiness protectio n has become a challe ngingtask on the design and experiment with various types of ve hic les. The top tube andunderbeam of the front of the car body is a major collis ion energy absorptio ncompone nts of vehic les. A good e nergy a bso rp tio n de vic e should tra ns fo rm a smuc h k ine tic e nergy a s po ss ib le into the structura l stra in e ne rgy in a nirre ve rs ib le pa tte rn d urin g c ra s hing. Multi-cell materia ls mainly for hone ycombmateria l and foam materia l have been widely applied in auto mobile bufferendergonic because of good energy absorption properties. Ba sed o n theoretica lanalys is model, we conducted a series of research and ana lys is to improve thecrashworthiness of the structure of multi-cell materia ls and energy absorptio ncharacteristics by us ing the explic it finite ele me nt techniq ue, meta model andsuitable optimization design method.At the beginning of the d issertation, recent deve lopme nts of crashworthinessoptimizatio n are brie fly summarized, and re searches on aluminium hone ycombmateria ls and high energy-absorptio n foam materia ls are also summarized. The n, thema in theoretical backgrounds are introduced, such as the explic it finite ele me nttechnique, endergonic structure crashworthiness ind icators, experimenta l designmethods and response surface method. After that, these theories are used to ana lyzeand optimize energy absorption characteristics of aluminum honeyco mb materia l andaluminum foam thin-walled components by use of nonlinear finite e leme nt codeLS-DYNA, software MATLAB and iSIGHT.In the study on the crashworthiness optimization des ign o f structure ofmulti-cell filled circ ular tubes, we firstly give the material mode l and finite ele me ntanalys is model, emp loy the factoria l design for selectio n according to the variab le offunction value (specific energy absorption and the maximum impact force)contributio n percentage. The n the optima l e xperime nta l design method is adopted tosample points, and the sequence response surface method is adopted to analys is andfitting the structure total strain energy obtained by nonlinear finite ele ment codels-dyna. Fina lly, the specific energy absorption about the approximate functio n express ion of the design variables o f two kinds of c ircular cross sectio nconfiguration structure can be optimized and compared. Ana lys is res ults show thatthe annular array distrib ution of circ ular cross sectio n is better than that ofrectangular array distributio n on crashworthiness. During the crashworthinessoptimizatio n of square, round, and tapered section foam filled thin-walledcompone nts on the optimization variables of foam materia l poisson’s ratio, wecompared the specific energy absorption o f these three section of foam filledthin-walled components, and fo und that endergonic characteristics of conical sectio nfoam filled thin-walled components is best, fo llowed by circular cross section, theendergonic characteristics of square cross section foa m filled thin-walledcompone nts is the worst.The metamodel and optimization a lgorithm used in this research process onoptimizatio n design o f multi-cell materia l thin-walled compone nts withcrashworthiness criterion has a reference for the crashworthiness optimizatio ndesign of d ifferent form of multi-cell materia ls to a certain e xtent. Meanwhile, theconc lus io ns are guid ing for the selectio n of structure shape and size in the practica lengineering application.