Study On Contact Mechanics Model Between Adjustable Brassiere And Breast Based On Finite Element

Adjustable brassiere,also known as shaping brassiere,is designed to shape the breast through the pressure of high elasticity fabric.While protecting the breast,it also makes the breast enlarged,lifted and gathered.The pressure and the shaping effect are important considerations in designing adjustable brassieres,and are also important factors for consumers when buying adjustable brassieres.Finite element analysis can be used to investigate the contact mechanics of the human body and the garment,simulating the pressure and deformation of the human body after wearing the garment.Therefore,this paper constructs a finite element contact mechanics model of the adjustable brassiere and the chest,aiming to investigate the interaction between the adjustable brassiere and the chest,and to realize a simulation of the wearing of adjustable brassieres with different material properties.The point cloud data of the human body wearing the adjustable brassiere is obtained through three-dimensional body scanning,and the chest surface is reconstructed by using the detection contour method in the point cloud processing software Geomagic Wrap.The geometric model of the chest is divided into a layer of 10 mm soft tissue,thorax and breast in the reverse engineering software Geomagic Design X.In Geomagic Design X,the geometric model of an adjustable brassiere in a semi-dressed state is constructed using a combination of forward and reverse modelling methods and divided into eight parts: cup,strap,wire,bone,upper band,band,side wing and back wing.The Young’s modulus of each component of the brassiere is obtained through fabric stretching experiments.In the finite element analysis software ABAQUS,the breast and soft tissue are set as linear elastic entities with different material parameters,the thorax is set as a rigid body,and the brassiere is set as a linear elastic shell with multiple components and materials to establish a finite element contact mechanics model of the adjustable brassiere and the chest.Twelve pressure test points are set up at the main areas of the body(shoulders,breasts,underarms and underbust)where the adjustable brassiere acts.The pressure values at each point are measured by the airbag pressure sensing system while the subject is wearing the adjustable brassiere.In Geomagic Design X,four shaping evaluation indicator values for the body are extracted before and after wearing the adjustable brassiere.Matched samples t-test is performed to compare the fitting results with the finite element contact mechanics model simulation results.It shows that the simulated results are not significantly different from the measured values,which means that the model is effective.Based on the validated model,the material parameters of the straps and cups are varied to investigate the influences of the Young’s modulus of the straps and cups on the pressure and shaping effect at the chest.The simulation results show that the contact pressure values at each pressure test point increase as the Young’s modulus of the straps and the cups increases,and the values of each shaping evaluation indicator decrease as the Young’s modulus of the straps and the cups increases.The regression equations for contact pressure,shaping evaluation indicator and Young’s modulus of the shoulder straps and cups are established by regression analysis.the finite element contact mechanics models with four thicknesses of soft tissues wearing the band of the brassiere are established to investigate the influence of soft tissue thickness on the contact pressure and shaping effect of the chest after wearing the brassiere.The simulation results show that the contact pressure and surface stress of the human body show a decreasing trend with the increase of soft tissue thickness,and the displacement of the human body surface shows an increasing trend with the increase of soft tissue thickness.The finite element contact mechanics model of the adjustable brassiere and the chest established in this paper can not only promote the exploration of the interaction mechanism between the brassiere and the chest,but also scientifically guide the design of the brassiere style structure and fabric selection,and optimize the brassiere design.In addition,it can also provide research ideas for the simulation of other garments and human body.