TPEE材料力学性能及其对床垫体压分布的影响

Mechanical properties of TPEE and its influence on pressure distribution of mattress

床垫材料是影响人-床界面压力的重要因素,为此研究热塑性聚酯弹性体(TPEE)用作垫层时人-床界面的体压分布。通过准静态压缩,测试TPEE及普通海绵的力学性能;采用体压测试,探究TPEE 3种密度(45,55,65 kg/m^(3))、人体5个部位及2种卧姿条件下对床垫减压性能的影响。结果表明:随着TPEE密度从45 kg/m^(3)增加到65 kg/m^(3),其屈服强度和压陷硬度逐渐增大。与50 kg/m^(3)的普通海绵相比,TPEE在所选密度下的硬度较小。TPEE的吸能性能随应力的变化而不同,3种密度间TPEE吸收的能量及吸能效率存在显著差异。其中,TPEE的最大吸能效率随密度的增大而减小,TPEE45(密度为45 kg/m^(3))吸能效率最大为30%。体压测试显示,与海绵垫层相比,TPEE垫层可显著降低人-床界面的最大压力。随TPEE密度的增大,臀部减压百分比逐渐减小,其余部位则先减小后增大。TPEE垫层更利于缓解肩胛-背部和臀部的压力,其减压百分比均大于25%。同时,TPEE密度、人体不同部位及卧姿三类因素的不同条件之间的减压百分比均存在显著差异。基于人体各部位重力,结合垫层材料力学性能及卧姿得出,垫层TPEE45的减压性能较好。

Since the mattress material is an important factor affecting the pressure of the human-bed interface,the distribution of body pressure on the interface of human-bed was analyzed using thermoplastic polyester elastomer(TPEE)as the cushion material of the mattress.The mechanical properties of TPEE and sponge were tested through the quasi-static compression.The body pressure measurement system was used to explore the effect of TPEE on the pressure relief of the mattress under three densities(45,55,65 kg/m^(3)),five human body parts and two lying positions.The results indicated that,when the density of TPEE increased from 45 to 65 kg/m^(3),the yield strength and compression stress value of TPEE gradually increased.Compared with the sponge of 50 kg/m^(3),the TPEE material had lower hardness under this density range.The elastic modulus,yield strength and compression stress values of sponge were higher than those of TPEE.The energy absorption properties of TPEE were varied with the change of stress,and there were significant differences in energy absorption and energy absorption efficiency among three densities.Besides,the maximum energy absorption efficiency of TPEE decreased with the increase of density,and the maximum energy absorption efficiency was 30%when the TPEE density was 45 kg/m^(3).In terms of the interfacial pressure distribution,compared with the sponge cushion,TPEE cushion could significantly reduce the maximum pressure of the human-bed interface.With the gradual increase in TPEE density,the decompression percentage of hip gradually decreased,while that of the other parts of human body decreased firstly and then increased.Moreover,the TPEE cushion was more conducive to relieve the pressure on the shoulder-back and hip in contrast with the rest of body,and the decompression percentage of these two parts were more than 25%.At the same time,there were significant differences in decompression percentages under different conditions for the TPEE density,different parts of the body,and lying postures.In addition,based on the stresses exerted on the mattress by various parts of the subject s body,combined with the mechanical properties of TPEE and lying positions,it was concluded that the TPEE cushion of 45 kg/m^(3)had better pressure relief performance on various parts of the human body in two lying positions.