Research On Seat Profile Design Based On Ideal Pressure Distribution And HPM Simulation

The automobile seat comfort not only provide satisfactory driving experience for occupant,but also increase the competitiveness of the automobile in the industry.The comfort of seat is compared and evaluated mainly by pressure distribution.In design,perfect pressure distribution is often adopted as design target by manufactures.Pressure distribution index can be used to evaluate the quality of seat surface design.However,when the main pressure distribution satisfies the main principle,the effect of it in improving the riding comfort is not significant.Therefore,it is very important to meet the main requirement of the comfort pressure distribution in design,in which tremendous difficulties exist.Therefore,a new forward design method of seat surface is put forward in this thesis,which uses the ideal pressure distribution and the contour of the seated human body to design the seat surface.Unlike the traditional seat design method,the surface is designed on the premise of ideal pressure distribution so that the acquired seat surface can meet the comfort requirement of the pressure distribution of most people.The design idea of this thesis is: After the human body is seated on the car seat,the seat surface will have a certain amount of depression,extract a number of coordinate points on the indentation surface,use the mathematical model of the sponge deformation to convert the ideal pressure into a sponge.The amount of deformation is compensated by a number of sponge deformations on the embossed surface to obtain the seat profile prior to being indented.This profile is the ideal profile of the surface contours taking into account the ideal pressure distribution and the human sitting posture.In order to get the ideal seat surface,we first use the measuring device and weighing device to get the size and weight of each part of HPM,and establish the geometric and finite element models of the H point machine.The seat plate and the back plate of the H point machine are designed based on the contour of the body surface when the human body is sitting,and are used to simulate the body surface state when the human is seated.Because the stiffness of the curved panel of the H point machine is large,it is not easy to deform,and the curved panel can be regarded as the pressure subsidence surface of the seat.Secondly,the ideal pressure distribution value is calculated based on the ideal pressure distribution cloud chart,and the ideal pressure value after thinning is mapped onto the surface of the seat by pressure mapping.In order to get the mathematical model of sponge deformation,a chair sponge was selected for simulation test.The relationship between the thickness of sponge,pressure and deformation was analyzed,and the mathematical model of sponge deformation was established,and the mathematical model was verified.The mathematical model of sponge deformation is used to calculate the deformation of sponge under certain pressure and a certain thickness and density.The seat surface obtained by compensating the amount of sponge on the collapsed surface is the ideal seat surface.In the case of the same force,the amount of the sponges of different shapes is different.For this reason,a plane sponge and a surface sponge are set up to carry out a simulation test.The displacement law and pressure distribution index of the point in the deformation of the sponge are compared and analyzed.Under the same force,the deformation of flat sponge is greater than that of curved sponge.The average pressure and maximum pressure are larger than that of curved sponge,which indicates that sponge shape will affect the ride comfort of seats.The existence of constraints is a complicated relation between HPM components,pressure distribution simulation each need to be gradually set up,in order to reduce the tedious process of setting,this paper chooses the H point machine in a simulation experiment and sponge assembly weight and no weight case,verify that the two group test sponge deformation error the amount and pressure distribution index is very small.This paper finally chose the static parameters of car seat and SUV seat design ideal type seat surface,geometric model and finite element model and then set up two seats by reverse and curved surface reconstruction,then the two seat pressure distribution simulation,error analysis on pressure distribution index,proved the ideal seat good comfort,in order to verify the positive seat design method is feasible.