| With the continuous improvement of material living standard,people's health awareness of participating in sports has been gradually enhanced.At the same time,frequent sports injuries have become a serious threat to personal safety.In addition to actively avoiding risks through sports skill training,consciously wearing sports protective equipment can better protect the body.The design of sports protective equipment is a process of multi-disciplinary integration.Based on the force protection performance of materials,this paper establishes a complete research system from protection mechanism to product design to performance evaluation.In this paper,the main contents include the following aspects:1.Through literature review and market research,comparative analysis on the performance of the motor equipment main raw material,selected compression absorption work(?W)and maximum transmission impact force(Fmax)as the key indicators of performance evaluation of protective protection.It is proved that rubber material can absorb more force energy and is suitable for internal soft lining,and plastic material can effectively resist external deformation and is suitable for external protection layer.The maximum transmission impact force of eucommia ulmoide gum(EU gum)lies between the rubber and plastic materials,and the unique shape memory function is also the potential advantage of the preparation of EU gum sports protection equipment.2.The EU gum was modified by physical foaming,and then the effects of vulcanization degree and foaming degree on the protection performance were studied by means of compression recovery,high-speed mechanical testing,SEM,DSC,TGA,etc.,and the optimal conditions for the protective materials of EU gum were determined to be the addition of 4 phr thermal expansion physical microspheres and 1 phr sulfur.At this time,the absorption work of compression recovery was 28 MJ·m-3 and the maximum transmission impact force was 750 N.The relationship between crystallinity and force protection performance of EU gum with temperature was studied by means of variable temperature X-ray diffraction(VTWAXD)and high-speed mechanical detection,there were distinct change trends before and after the melting point.The micro-phase structure of the high-force EU gum nanocomposite is put forward as follows:the crystallize region is resistant to instantaneous high-speed force,the amorphous region absorbs quasi-static compression deformation,and the appropriate three-dimensional crosslink network makes it have shape memory property.3.Comparing the designed EU gum sports protection equipment with the market products,it is found that the force protection efficiency of EU gum per unit thickness is 10%/mm-1,which has obvious advantages compared with Li Ning leg protection board and Decathlon leg protection board,and the protection efficiency will gradually decrease with the increase of force energy.Besides,the increase of the contact area between the sports protection and the human body will improve the protection performance.4.Take human body pain perception as a quantitative index to evaluate the protective performance of sports equipment,based on the design of high-speed mechanical testing equipment,pendulum force angle and Fmax show clear linear increase relation.The statistical analysis of survey results found that the true threshold force for pain perception was 1362 N,and there was a 400 percent decrease in human body pain before and after wearing the EU gum football leg pads,which showed that the sports protective equipment plays an important role in force protection. |
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