Numerical and empirical modeling of peak deceleration and stress analysis of polyurethane elastomer under impact loading test

2020 ◽  
Vol 89 ◽  
pp. 106594
Author(s):  
Behrang Shamsadinlo ◽  
Mohammad Rauf Sheikhi ◽  
Ozgur Unver ◽  
Bora Yildirim
2001 ◽  
Vol 67 (662) ◽  
pp. 1696-1701
Author(s):  
Takaaki SARAI ◽  
Noriyuki NAGAYAMA ◽  
Hiroyuki HASHIZUME

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Yunbing Hu ◽  
Tianzhu Duan ◽  
Penghui Xian ◽  
Liang Chen

In order to explore the impact of freeze-thaw temperature on the sputtering rate of water-saturated yellow sandstone under impact loading, in this paper, the Hopkinson pressure bar is used to conduct impact loading test on the water-saturated yellow sandstone at the same strain rate (74.22 s−1) under five different freeze-thaw temperatures. After impact loading, the yellow sandstone fragments are graded and screened by using the sizing screen, and the mass of fragments with different particle sizes after screening is counted. By transforming the fragments into spheres with the corresponding particle sizes, and combining the dissipated energy, the surface specific energy of yellow sandstone with different freeze-thaw temperatures is calculated. Finally, the sputtering rate of the fragments is obtained by using the relationship of total work, dissipated energy, and kinetic energy. The main conclusions are as follows: The freeze-thaw temperature has a significant effect on the fracture degree of yellow sandstone. The lower the freeze-thaw temperature is, the higher the fracture degree of yellow sandstone is, and the smaller the particle size distribution of fragments is. The fractal dimension of yellow sandstone increases with the decrease of freeze-thaw temperature, indicating that the damage of yellow sandstone is more serious. The dissipative energy of yellow sandstone increases with the decrease of freezing temperature, while the kinetic energy increases gradually when the freeze-thaw temperature is −30°C to −15°C and decreases gradually when the freeze-thaw temperature is −15°C to −5°C. The surface area and surface specific energy of yellow sandstone fragments both increase with the increase of freeze-thaw temperature. And the sputtering rate of yellow sandstone fragments increases gradually at freezing temperature from −30°C to −15°C and decreases gradually at −15°C to −5°C. Therefore, from the perspective of dynamic destruction process, the sputtering of yellow sandstone fragments at freezing temperatures of −15°C, −20°C, and −30°C is more intense than that at −5°C and −10°C. The results can provide some guidance for production in winter and winter regions.


2007 ◽  
Vol 44 (2) ◽  
pp. 201-220 ◽  
Author(s):  
Bengt H Fellenius ◽  
Jaime A Santos ◽  
António Viana da Fonseca

The 2nd International Conference on Site Characterization (ISC'2), held in 2004, included a seminar for prediction of pile capacity involving three 6 m embedment length test piles, one 350 mm square driven concrete pile, and two 600 mm diameter, strain-gage instrumented, bored piles. Invited predictors were provided with results of in situ, laboratory tests and dynamic tests. Test layout, soil information, and pile data are presented with calculations of pile capacity and load distribution, submitted predictions, and results of the static loading tests. The CPT-calculated capacities show considerable scatter—total values ranged from 500 to 1400 kN for the driven pile and from 1000 to 1900 kN for the bored piles. The static loading test on the driven pile showed an offset limit load of 1200 kN and a plunging capacity of 1500 kN. Despite pile movements of 100 mm for 1200 kN of applied load, neither of the bored piles showed signs of having reached an ultimate resistance value. Effective stress analysis of strain measurements for the bored piles showed the data to correlate to a β coefficient of 1.0 and a toe coefficient of 16. Most submitted predictions underestimated the capacity of the driven pile and overestimated the capacities of the bored piles.Key words: pile capacity, effective stress analysis, shaft and toe resistances, β coefficient, CPTU, dynamic testing.


2021 ◽  
pp. 1-13
Author(s):  
Mehdi Koohmishi ◽  
Alireza Azarhoosh

Impact loads generated from the dynamic effect of passing trains can exacerbate the degradation level of ballast aggregate of railway track. To diminish the induced impact loads, the use of crumb rubber (CR) in the ballast course is characterized as a well-established procedure related to the modification of utilized material. Nonetheless, more in-depth assessments of size and percentage of CR particles combined with ballast aggregate are still required. The present study evaluates the influence of size and content of CR particles used for degradation reduction of ballast aggregate subjected to impact loading. For this purpose, a large-scale impact loading test is carried out on prepared specimens of aggregate by considering the initial gradation, subgrade condition, as well as the size and content of CR particles. The results indicate less ballast degradation for a higher percentage of CR particles. Meanwhile, the enhancement of rubber modified ballast against deterioration is further highlighted in the case of rigid subgrade. In addition, incorporation of larger-sized CR particles (12.5–25 mm) in a ballast specimen comprising more uniform gradation of aggregate can more effectively diminish the amount of degradation. Nevertheless, using smaller-sized CR particles (4.75–9.5 mm) for a ballast sample consisting of a broader range of sizes can better improve resistance against degradation.


2011 ◽  
Vol 82 ◽  
pp. 589-593
Author(s):  
Kazuyoshi Ishibashi ◽  
Satoshi Katsuki ◽  
Akinori Hirose ◽  
Kenji Tanaka

This paper presents an experimental study on the impact absorption effect of the device which utilizes both shear deformation ductility of rubbers and a wedge mechanical system. Two types of experiments, i.e., static and impact loading, are carried out. Rate effect on resistance of the device is checked by comparison between static loading test results. The impact absorption effect is discussed by comparisons of the impact loading test between the impact load and the transmitting load. The other some impact absorption effects are discussed on the impact loading test.


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