| The whole system of sofa frame is composed of three subsystems:seat frame,backrest frame and armrest frame,among which the seat frame frame system is the most complex and challenging.This research attempts to carry on the mechanics analysis to the single sofa's seat frame,and uses the finite element analysis technology to carry on the quite thorough research to the structure optimization design,hoped to make the certain contribution to the single sofa's frame optimization design.According to the actual investigation of factory g,this paper sums up four kinds of sofa frame with typical structural characteristics.Taking poplar multilayer board as the main material and pine as the contrast material,it analyzes the main stress parts of the frame,calculates the stress formula,and then combines the theoretical basis of the finite element method to simulate with ANSYS Workbench software.The main research results and conclusions of this paper are as follows:?1?Based on the three-point bending method,the material properties of poplar multilayer plates are measured by deflection method and strain gauge method.The average value ofmeasured by deflection method is 6351MPa,the average value ofmeasured by strain gauge method is 6823MPa,and the relative error is 6.9%.Combined with the deduction of stiffness separation method,the reason of error is analyzed.The mid point deflection measured by deflection method is actually the total deflection under the joint action of bending moment and shear force,but only the bending deflection is calculated in calculation,while the mid point deflection measured by strain gauge method is caused by pure bending,so the data measured by strain gauge method is more valuable for reference.?2?Four typical base frame structures are summarized from three aspects:size,corner joint,side plate and front and rear beam connection.According to the theory and method of ergonomics,the size range of seat frame is concluded.The seat width is about 550mm,and the seat depth is about 680mm.?3?Combined with the theory of material mechanics,the physical model of sofa seat frame is simplified,and the theoretical simplified model of front rail is obtained,and the stress analysis of statics and dynamics is carried out in detail.In the static part,the superposition method is used to solve the problem of statically indeterminate beam of front guide rail.It is found that the maximum deflection of front guide rail occurs between the first and the last serpentine spring and side plate under the action of uniform load.The maximum deflection of poplar multilayer plate is 4.54×10-3mm,and the maximum deflection of pine is 4.72×10-3mm??4?The finite element method is used to verify the correctness of the theoretical analysis of the front guide rail crossbeam,and ANSYS is used to simulate the stress of four different types of seat frames under the same load,and the structural form of C type seat frame is the best.According to the test standard of?QB/T 4191-2011?,the impact simulation of C frame is carried out,and it is found that the maximum stress value of the frame is 22.11mpa,which is greater than the bending ultimate strength of the material by 17.02MPa.Combined with the design exploration response surface optimization module to optimize the size.The optimized section is 48mm wide and 28mm thick.The maximum stress is 13.12mpa,which is 40.7%less than that before optimization.Then,the fatigue strength of the optimized model was verified by using DesignLife plug-in.The minimum number of fatigue life of the detection device was28784 times,which was more than 25000 times of the fatigue strength value in?QB/T4191-2011?test standard.The size design optimization meets the standard requirements. |
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