Preparation Of Automobile Collision Dummy Skin And Its Mechanical Properties

With the rapid development of modern industry in China,automobile manufacturing technology is moving in the direction of diversification,high technology,and modernization.The construction of a powerful transportation conuntry is an important support for the realization of the goal of strengthening the socialist modernization.It is an inevitable requirement of meeting the people’s growing needs for a better life and enhancing the development potential to improve the national transport network.The simulation,testing and testing of vehicle conditions will be more comprehensive and systematic.Further,the dummy simulation techniques used in automobile crash tests will also be more advanced.As the first collision barrier,the dummy’s skin is the part that directly contacts the outside world in an automobile crash test and plays an important role.Its material properties have a great influence on the biomechanical response of the dummy during the entire collision process.The design of the dummy’s skin should ensure that both the external impact and other related signals could be accurately transmitted to the internal sensor.On the other hand,the design should also ensure that the dummy can be used rycally.The appearance of view,uninstall can be partially or completely restored to its original appearance.Therefore,the raw materials chosen for the preparation of artificial skin should have not only a certain degree of flexibility,but also should have excellent formability,which are easy to follow-up into a variety of human body shape and easy to connect in the installation.Through several attempts and screening,this paper chooses linear low density polyethylene and general-purpose polyvinyl chloride as the two kinds of basic materials,and selects thermoplastic polyurethane as the mixed material.Pretreatment is set for the five blending ratios of 0%,20%,40%,60% and 80%.The physical blending temperature of the linear low-density polyethylene and the thermoplastic polyurethane is 180℃-190℃,and the physical blending temperature of the polyvinyl chloride and the thermoplastic polyurethane is 170℃-180℃.Knead for 10 min at a speed of 50 rad/min,remove the semi-finished product,and press the flat vulcanizer to make the uniform thin slice skin samples with the thicknesses of 2 mm and 4 mm respectively.100%LLDPE,80%LLDPE + 20%TPU,60%LLDPE + 40%TPU,40%LLDPE + 60%TPU,20%LLDPE + 80%TPU,100%PVC,80%PVC+20%TPU,60%PVC + 40%TPU,40%PVC + 60%TPU,20%PVC + 80%TPU,the above ten sets of skin samples were tested for tensile strength,impact strength and Shore hardness.Through a large scale ratio of preparation and basic mechanical properties testing,it can be seen that the samples of the blend of linear low density polyethylene and thermoplastic polyurethane are hard and tough with obvious yielding and plastic deformation,yield stress decreases with the increase of thermoplastic polyurethane content,Although the impact strength showed a downward trend,the amount of deformation increased significantly.Polyvinyl chloride and thermoplastic polyurethane blends sample soft and elastic,no obvious yield and plastic deformation.The elongation of 20%LLDPE + 80%TPU was the highest,reaching 277.79%.The elongation of 60%PVC + 40%TPU was the lowest,148.94%.According to the results of hardness test,it is found that the composition of PVC and TPU is better,and the strength of LLDPE and TPU is higher.The regression analysis of the impact properties of the sample and the relationship between the hardness index and the material formula using the obtained data shows that 100%LLDPE,80%LLDPE+20%TPU,60%LLDPE+40%TPU,40%LLDPE+60%TPU,20%LLDPE + 80%TPU,five groups of dummy skin samples,impact strength,hardness index and raw material ratio generally meet the negative correlation,a linear regression fitting equation can perform performance prediction and raw material ratio reverse.100%PVC,80%PVC + 20%TPU,60%PVC + 40%TPU,40%PVC + 60%TPU,20%PVC + 80%TPU,five groups of artificial skin samples,the impact strength,hardness and raw material ratio generally conform to the parabolic relationship.With the addition of thermoplastic polyurethane,the impact strength first decreased to the lowest point and then rebounded.The quadratic regression equation could predict the performance and reverse the raw material ratio.Through the large scale regression analysis of the raw material ratio and mechanical properties,prediction and design of the sample formula according to the required performance,it can meet the performance requirements of different types of collision tests on the skin of the dummy.Through the law of fitting,the ratio of material blending can be reversed,and it is expected to provide a reference for subsequent experiments.