scholarly journals Laboratory Testing on Energy Absorption of High-Damping Rubber in a New Bolt for Preventing Rockburst in Deep Hard Rock Mass

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Lu Chen ◽  
Qingwen Li ◽  
Jianming Yang ◽  
Lan Qiao
Keyword(s):  
Rock Mass ◽  
Energy Absorption ◽  
Hard Rock ◽  
Split Hopkinson Pressure Bar ◽  
Absorption Characteristic ◽  
Hopkinson Pressure Bar ◽  
Mining Depth ◽  
New Energy ◽  
High Damping Rubber ◽  
Energy Absorbing

With the increase in mining depth, the deep hard rock mass is under threat of rockburst under high geostress, high temperature, high osmotic pressure, and strong disturbance. To reduce the probability and strength of rockburst, a new energy-absorbing bolt for guaranteeing the stability of deep hard rock mass was developed utilizing the energy absorption characteristic of high-damping rubber. To analyze the practicability and obtain the quantified behaviors of this new energy-absorbing bolt, a series of impact tests on specimens of high-damping rubber, granite, and granite–rubber composite specimens was carried out by a split Hopkinson pressure bar (SHPB) method. Further, considering the different working depths with different rock temperatures, the dynamic energy-absorbing characteristics of high-damping rubber under different temperatures were tested. The testing results show that the new energy-absorbing bolt can consume the storage energy in host rock effectively, and the environmental temperature will produce certain effects on the energy-consuming rate. In addition, the optimal energy-absorbing thickness–diameter ratio of high-damping rubber was confirmed by SHPB tests.

scholarly journals Stress Attenuation and Energy Absorption of the Coral Sand with Different Particle Sizes under Impacts

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 545
Author(s):  
Xiao Yu ◽  
Li Chen ◽  
Qin fang ◽  
Wuzheng Chen
Keyword(s):  
Energy Absorption ◽  
Stress Wave ◽  
Wave Attenuation ◽  
Split Hopkinson Pressure Bar ◽  
Particle Size Effect ◽  
Particle Sizes ◽  
Hopkinson Pressure Bar ◽  
Coral Sand ◽  
Stress Zone ◽  
Pressure Bar

The stress wave attenuation and energy absorption in the coral sand were respectively investigated. A series of experiments were carried out by using a new methodology with an improved split Hopkinson pressure bar (SHPB). Four types of coral sand, i.e., particle sizes of 1.18–0.60 mm, 0.60–0.30 mm, 0.30–0.15 mm, and 0.15–0.075 mm, were carefully sieved and tested. Significant effects of coral sand on stress wave attenuation and energy absorption were observed. Correlation between stress wave attenuation and energy absorption of coral sand was validated. Conclusions on particle size effect of stress wave attenuation and energy absorption, which support each other, were drawn. There existed a common critical stress zone for coral sand with different particle sizes. When the stress below this zone, sand with small particle sizes attenuates stress wave better and absorb energy more; when the stress beyond this zone, sand with larger particle sizes behave better on stress wave attenuation and energy absorption.

scholarly journals Influence of Crack Geometry on Dynamic Damage of Cracked Rock: Crack Number and Filling Material

2020 ◽  
Vol 11 (1) ◽  
pp. 250
Author(s):  
Feili Wang ◽  
Shuhong Wang ◽  
Zhanguo Xiu
Keyword(s):  
Energy Absorption ◽  
Split Hopkinson Pressure Bar ◽  
Mineral Exploration ◽  
Damage Variable ◽  
Filling Material ◽  
Hopkinson Pressure Bar ◽  
Filling Materials ◽  
The Stability ◽  
Pressure Bar ◽  
Dynamic Damage

The dynamic damage of cracked rock threatens the stability of rock structures in rock engineering applications such as underground excavation, mineral exploration and rock slopes. In this study, the dynamic damage of cracked rock with different spatial geometry was investigated in an experimental method. Approximately 54 sandstone specimens with different numbers of joints and different filling materials were tested using the split Hopkinson pressure bar (SHPB) apparatus. The energy absorption in this process was analyzed, and the damage variable was obtained. The experimental results revealed that the dynamic damage of cracked rock is obviously influenced by the number of cracks; the larger the number, the higher the energy absorption and the bigger the dynamic damage variable. Moreover, it was observed from the dynamic compressive experiments that the energy absorption and the dynamic variable decreased with the strength and cohesion of the filling material, indicating that the filling material of crack has considerate influence on the dynamic damage of cracked rock.

scholarly journals Antiknock Performance of Interlayered High-Damping-Rubber Blast Door under Thermobaric Shock Wave

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Xiudi Li ◽  
Chaoyang Miao ◽  
Qifan Wang ◽  
Zhengang Geng
Keyword(s):  
Shock Wave ◽  
Split Hopkinson Pressure Bar ◽  
Front Surface ◽  
Underground Structures ◽  
Hopkinson Pressure Bar ◽  
Maximum Displacement ◽  
Average Strain Rate ◽  
Split Hopkinson ◽  
High Damping Rubber ◽  
Pressure Bar

The long duration and high impulse shock wave of thermobaric bomb threatens the security of underground structures. To obtain high resistance blast door against thermobaric shock wave, firstly, the dynamic mechanic property of high damping rubber was studied by split Hopkinson pressure bar (SHPB) equipment and the stress-strain relationship of high damping rubber under average strain rate of 5200/s was obtained. Secondly, the numerical model of interlayered high-damping-rubber blast door was established with ANSYS/LS-DYNA code based on test results, and the antiknock performance of interlayered high-damping-rubber blast door under thermobaric shock wave was analyzed by contrast with ordinary blast door. The results showed that the midspan displacement of the blast door decreased firstly and then increased with the increase of thickness of the high-damping-rubber interlayer, and the optimal thickness of the high-damping-rubber interlayer for energy consuming was 150 mm in the calculation condition of this paper. With the increase of the distance between the interlayer and the front surface of the door, the midspan displacement of the blast door decreased continually. The midspan maximum displacement of interlayered high-damping-rubber blast door decreased 74.5% in comparison to ordinary blast door. It showed that the high-damping-rubber structure can effectively improve the antiknock performance of blast door under thermobaric shock wave.

Deformation Mode Dependency on Strain Rate Sensitivity of Volume Resistivity in TRIP Steel

2013 ◽  
Vol 535-536 ◽  
pp. 473-476 ◽  
Author(s):  
Takeshi Iwamoto ◽  
Shiro Yamanaka ◽  
Alexis Rusinek
Keyword(s):  
Trip Steel ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Rate Sensitivity ◽  
Volume Resistivity ◽  
Deformation Mode ◽  
Absorption Characteristic ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Pressure Bar

With a phenomenon of strain-induced martensitic transformation, TRIP steel is expected to show excellent impact energy absorption characteristic. It is important for an improvement of a reliability of TRIP steel to evaluate an amount of martensite. In this study, AISI304, which is a kind of TRIP steel, is deformed plastically by a conventional material testing machine and the split Hopkinson pressure bar apparatus. During the deformation of TRIP steel, a circuit based on the Kevin double bridge measures change in volume resistivity which has a correlation with the amount of martensite. Experimental results show that the change in volume resistivity during the process of deformation at various strain rates.

scholarly journals Analisis Numerik Penyerapan Energi pada Sabot untuk Pengujian Bird Strike

2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Riskha Agustianingsih
Keyword(s):  
Energy Absorption ◽  
Split Hopkinson Pressure Bar ◽  
Bird Strike ◽  
Hopkinson Pressure Bar ◽  
Crushing Force ◽  
Split Hopkinson ◽  
Pressure Bar

abstrak - Pengujian Bird Strike dilakukan menggunakan alat SHPB (Split Hopkinson Pressure Bar) yang menembakkan sabot (wadah burung). Pada ujung alat SHPB, sabot akan dihentikan oleh stopper sehingga burung akan terlepas dan meluncur dengan bebas hingga mengalami tumbukan dengan komponen uji. Sabot harus memaksimalkan kecepatan burung ketika keluar (terlepas dari sabot). Berdasarkan persamaan impuls dan momentum, hal ini dapat diperoleh dengan meminimalkan waktu tumbukan sehingga gaya impulsnya akan meningkat. Tujuan penelitian ini adalah mengetahui waktu tumbukan, pola grafik Energy Absorption (EA), Peak Crushing Force (PCF), dan Mean Crushing Force (MCF). Dari parameter tersebut, maka diperoleh sabot yang diinginkan berdasarkan waktu tumbukan tersingkat, PCF dan MCF tertinggi, serta EA terendah. Simulasi dilakukan menggunakan perangkat lunak elemen hingga (Abaqus CAE) berdasarkan variasi material (AA6061-T6, S355, dan AISI 1340) sabot. Berdasarkan hasil dan pembahasan, diperoleh bahwa waktu tumbukan paling singkat dimiliki variasi material AISI 1340 dengan nilai 0.00071 s. EA terendah untuk variasi material dimiliki oleh AISI 1340, yaitu sebesar 2.51 kJ. PCF tertinggi untuk variasi material dimiliki oleh material AISI 1340, yaitu 466 kN. Ditentukan bahwa berdasarkan nilai waktu (t) paling singkat, PCF, MCF paling tinggi, dan EA paling rendah, maka diperoleh material AISI 1340 sebagai material yang diinginkan karena paling berpengaruh terhadap peningkatan kecepatan burung setelah keluar dari sabot.

Study of dynamic compressive behaviour of aramid and ultrahigh molecular weight polyethylene composites using Split Hopkinson Pressure Bar

2016 ◽  
Vol 51 (1) ◽  
pp. 81-94 ◽  
Author(s):  
Khubab Shaker ◽  
Abdul Jabbar ◽  
Mehmet Karahan ◽  
Nevin Karahan ◽  
Yasir Nawab
Keyword(s):  
Molecular Weight ◽  
Strain Rate ◽  
Energy Absorption ◽  
Split Hopkinson Pressure Bar ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Hopkinson Pressure Bar ◽  
Ultrahigh Molecular Weight ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
Polyethylene Composites

In this paper, high strain rate compression properties of aramid and ultrahigh molecular weight polyethylene composites in the out-of-plane direction are tested at room temperature on a Split Hopkinson Pressure Bar apparatus. Tests were conducted on composites reinforced with woven or Uni-Directional (UD) fabrics made from aramid or ultrahigh molecular weight polyethylene as well as on composites reinforced with hybrid reinforcement. The strain rate is varied in the tests by changing the projectile shooting pressure. Four different pressures 2, 4, 6 and 8 bar were selected to change the strain rate. Stress–strain and energy absorption behaviour of eight type of samples were noted. Hybrid samples showed better performance in the energy absorption compared with other samples.

Study on dynamic strength of sandstone based on SHPB numerical experimentation

2020 ◽  
Author(s):  
Wengang Zhang ◽  
Fansheng Meng ◽  
Qi Wang
Keyword(s):  
Rock Mass ◽  
Dynamic Loading ◽  
Split Hopkinson Pressure Bar ◽  
Axial Loading ◽  
Dynamic Strength ◽  
Experimental Sample ◽  
Hopkinson Pressure Bar ◽  
Rock Engineering ◽  
Static Tests ◽  
Numerical Experimentation

<p>It is unavoidable that in rock engineering practices such as mining and tunnel constructions rocks are subjected to dynamic loading impacts including blasting, seismic loading, rock burst, and so on. The mechanical parameters for rock strength obtained via traditional static tests are not capable of characterizing the dynamic strength of rock mass. Therefore, the conventionally adopted tests cannot be further applied to guide the design of rock engineering subjected to dynamic loadings. Therefore the determination of the dynamic strength is essential for practical engineering. In this study, sandstone is chosen as the experimental sample for Split Hopkinson Pressure Bar (SHPB) numerical simulation by FLAC3D. The validation demonstrated that rocks are prone to fail under dynamic loading impacts. Extensive simulations are also carried out to investigate the development of rock dynamic strength and evolution process of energy accumulation and release in rock mass for samples of various sizes subjected to different levels of dynamic loading and axial loading. The simulation results may provide design guidance for the safety protection of rock engineering subjected to dynamic impacts.</p>

Improved Crashworthy Aircraft Seat Design

2002 ◽  
Author(s):  
Kash Kasturi ◽  
Peter Kwok
Keyword(s):  
Energy Absorption ◽  
Integrated Design ◽  
Model Verification ◽  
Structural Members ◽  
Additional Energy ◽  
Precise Control ◽  
Occupant Protection ◽  
Passenger Seat ◽  
New Energy ◽  
Energy Absorbing

An innovative transport aircraft passenger seat concept for superior occupant protection, meeting all structural requirements used in typical seat designs was developed. This was accomplished with the use of new energy-absorbing structural members and precise control of seat deformation characteristics. Advanced dynamic finite element modeling technique was utilized to analyze the integrated design of the seat, occupants, restraints and energy absorbing elements. Results from certification tests on an existing seat design were used to validate the analytical model. Verification studies have shown good correlation between the analytical simulations and the test data. In addition, further improvements to occupant protection of this new aircraft seat design were accomplished by incorporating the seat back tilt mechanism coupled with the use of shoulder belt. The seat back tilt mechanism utilizes similar energy-absorption concept and provides additional energy absorption while being pulled forward by the shoulder belt.

scholarly journals Constitutive Parameters Identification of AZ31B-H24 Magnesium Alloy and Energy-Absorption Analysis in Structural Panel Use

2018 ◽  
Vol 153 ◽  
pp. 01004
Author(s):  
Yuedong Yang ◽  
Jiqing Chen ◽  
Fengchong Lan ◽  
Wu Zeng ◽  
Zhengwei Ma
Keyword(s):  
Magnesium Alloy ◽  
Constitutive Model ◽  
Energy Absorption ◽  
Split Hopkinson Pressure Bar ◽  
Parametric Identification ◽  
Hopkinson Pressure Bar ◽  
Curve Fit ◽  
Wide Range ◽  
Pressure Bar ◽  
Constitutive Parameters

As a novel lightweight material, AZ31B magnesium alloy is considered as the most potential material to instead baseline steel in some automotive parts. However, their structural use is quite limited and so far proper numerical modeling has not been developed to represent magnesium alloy. In present study, the Split Hopkinson Pressure Bar (SHPB) test is utilized to investigate material dynamic mechanism for AZ31B-H24 over a wide range of strain rates from 1389 s-1 to 7296 s-1. Parametric identification for Johnson-Cook (J-C) constitutive model available in the commercial finite element package LS-DYNA is carried out. Proper parameters are obtained by curve fit using genetic algorithm with experimental results. Constitutive model after parametric identification is applied to automotive outer panels for crashworthiness analysis. Energy absorption with magnesium alloy substituted baseline steel under lightweight 51.18% is obtained and the key problem of thin-walled magnesium alloy applied in automotive structure is advanced.

scholarly journals Compressive Properties and Energy Absorption Characteristics of Extruded Mg-Al-Ca-Mn Alloy at Various High Strain Rates

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 87
Author(s):  
Chongchen Xiang ◽  
Zhendong Xiao ◽  
Hanlin Ding ◽  
Zijian Wang
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Energy Absorption ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Extrusion Direction ◽  
Rate Sensitivity ◽  
Hopkinson Pressure Bar ◽  
Deformation Ability ◽  
Absorption Characteristics

This paper is focused on the mechanical properties and the energy absorption characteristics of the extruded Mg-Al-Ca-Mn alloy in different compression directions under high strain rate compression. Compressive characterization of the alloy was conducted from the high strain rate (HSR) test by using a Split Hopkinson Pressure Bar (SHPB). Results show that the investigated alloy exhibits a strong strain rate sensitivity. With the rise of strain rate, the compressive strength is increased significantly, and the deformation ability also improves. When compressed along the extrusion direction, as the strain rate increases, the total absorbed energy E, the crush force efficiency (CFE), and the specific energy absorption SEA of Mg-Al-Ca-Mn alloy are all greatly improved as compared with those obtained along other compression directions.

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