Shock Absorption Effect on Particle Fragmentation and Microstructural Features of Vacuum-Kinetic-Sprayed Al2O3 Film on Polycarbonate Substrate

Author(s):  
Hyungkwon Park ◽  
Hansol Kwon ◽  
Jaeick Kim ◽  
Changhee Lee
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xiaoying Liu ◽  
Yong Yue ◽  
Xuyang Wu ◽  
Yanhua Hao ◽  
Yong Lu

On the basis of computer aided modeling technology, this paper proposes a porous structure modeling method based on Grasshopper visual programming language and Unigraphics NX (UG) secondary development platform. The finite element model of the foot was established, and then models of shoe soles with four basic porous structures of cross, diamond, star, and x were established. Each structure was set with a cylindrical radius of 1, 2, and 3 mm, and a total of 12 porous structure sole models were established. The shock absorption effect of the sole on the foot was evaluated by the deformation of the sole, the peak plantar pressure, and the peak stress of metatarsal bones. It is found that the maximum value of the sole deformation of the diamond porous sole is 4.725 mm, the peak plantar pressure is 105.1 Pa, and the first and second metatarsal peak pressures are 2.230 MPa and 3.407 MPa, which have the best shock absorption effect. It shows that the porous structure plays an important role in the cushioning of the sole. The biomechanical effects of porous soles on feet are studied by computer-aided technology and finite element analysis. This study provides a new research method for the cushioning design of shoe soles and has important reference value for the design of footwear.


2019 ◽  
Vol 16 (4) ◽  
pp. 625-645
Author(s):  
Haixu Yang ◽  
Feng Zhu ◽  
Haibiao Wang ◽  
Liang Yu ◽  
Ming Shi

Purpose The purpose of this paper is to describe the structure of nonlinear dampers and the dynamic equations, and nonlinear realization principles and optimize the parameters of nonlinear dampers. Using the finite element method to analyze the seismic performance of the frame structure with shock absorber. Design/methodology/approach The nonlinear shock absorber was installed in a six-storey reinforced concrete frame structure to study its seismic performance. The main structure was designed according to the eight degree seismic fortification intensity, and the time history dynamic analysis was carried out by Abaqus finite element software. EL-Centro, Taft and Wenchuan seismic record were selected to analyze the seismic response of the structure under different magnitudes and different acceleration peaks. Findings Through the principle study and parameter analysis of the nonlinear shock absorber, combined with the finite element simulation results, the shock absorption performance and shock absorption effect of the nonlinear energy sink (NES) nonlinear shock absorber are given as follows: first, the damping of the NES shock absorber is satisfied, and the linear spring stiffness and nonlinear stiffness of the shock absorber are based on the relationship k1=kn×kl2, so that the spring design length is fixed, and the linear stiffness of the shock absorber can be obtained. The nonlinear shock absorber has the characteristics of high rigidity and frequency bandwidth, so that the frequency is infinitely close to the frequency of the main structure, and when the mass of the shock absorber satisfies between 0.056 and 1, a good shock absorption effect can be obtained, and the reinforced concrete with the shock absorber is obtained. The frame structure can effectively reduce the seismic response, increase the natural vibration period of the structure and reduce the damage loss of the structure. Second, the spacer and each additional shock absorber have a small difference in shock absorption effect. After the shock absorber parameters are accurately calculated, the number of installations does not affect the shock absorption effect of the structure. Therefore, the shock absorber is properly constructed and accurately calculated. Parameters can reduce costs. Originality/value New shock absorbers reduce earthquake-induced damage to buildings.


2007 ◽  
Vol 23 (2) ◽  
pp. 119-127 ◽  
Author(s):  
Hung-Ta Chiu ◽  
Tzyy-Yuang Shiang

The purpose of this study was to investigate the effects of insoles and additional shock absorption foam on the cushioning properties of various sport shoes with an impact testing method. Three commercial sport shoes were used in this study, and shock absorption foam (TPE5020; Vers Tech Science Co. Ltd., Taiwan) with 2-mm thickness was placed below the insole in the heel region for each shoe. Eight total impacts with potential energy ranged from 1.82 to 6.08 J were performed onto the heel region of the shoe. The order of testing conditions was first without insole, then with insole, and finally interposing the shock absorption foam for each shoe. Peak deceleration of the striker was measured with an accelerometer attached to the striker during impact. The results of this study seemed to show that the insole or additional shock absorption foam could perform its shock absorption effect well for the shoes with limited midsole cushioning. Further, our findings showed that insoles absorbed more, even up to 24–32% of impact energy under low impact energy. It seemed to indicate that insoles play a more important role in cushioning properties of sport shoes under a low impact energy condition.


Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 18
Author(s):  
Takahiro Wada ◽  
Hiroshi Churei ◽  
Mako Yokose ◽  
Naohiko Iwasaki ◽  
Hidekazu Takahashi ◽  
...  

Face guards (FGs) are protectors that allow for the rapid and safe return of athletes who are to play after sustaining traumatic facial injuries and orbital fractures. Current FGs require significant thickness to achieve sufficient shock absorption abilities. However, their weight and thickness render the FGs uncomfortable and reduce the field of vision of the athlete, thus hindering their performance. Therefore, thin and lightweight FGs are required. We fabricated FGs using commercial glass fiber-reinforced thermoplastic (GFRTP) and carbon fiber-reinforced thermoplastic (CFRTP) resins to achieve these requirements and investigated their shock absorption abilities through impact testing. The results showed that an FG composed of CFRTP is thinner and lighter than a conventional FG and has sufficient shock absorption ability. The fabrication method of an FG comprising CFRTP is similar to the conventional method. FGs composed of commercial FRTPs exhibit adequate shock absorption abilities and are thinner and lower in weight as compared to conventional FGs.


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