The Behavior of Propagation of the Impact Stress Wave in Human Bones of Lower Limb by high-speed Photoelastic Analysis

Impact stress wave propagating through porous materials is investigated in order to examine the ability of the shock absorbing effect. The specimens are modeled as the porous medium with different porous diameters made of the acrylic resin plate. When these models are impacted with different impact velocities, the impact stress waves propagating before and after the porous parts are measured using the strain gages in the experiments. As the reduction effect of the impact stress wave propagating in the porous medium, we pay attention to the maximum stresses and the duration times from the histories of the impact stress waves. One-dimensional wave theory and dynamic element method simulated this model are applied in order to explain these phenomena.

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Failure behavior of the surrounding rock of jointed rock masses in a gold mine under impact disturbance

10.21203/rs.3.rs-236125/v1 ◽

2021 ◽

Author(s):

Peng Li ◽

Yunquan Wu ◽

Meifeng Cai

Keyword(s):

Stress Wave ◽

Shear Failure ◽

Jointed Rock ◽

Surrounding Rock ◽

Tensile Failure ◽

Tensile Shear ◽

Underground Engineering ◽

Impact Stress ◽

The Stability ◽

The Impact

Abstract The impact disturbance has an important influence on the safety of underground engineering openings. In this paper, based on the in-situ stress measurement and structural plane investigation, the model of jointed rock roadway was established using the discrete element method (3DEC) to study the instability and failure characteristic of roadway surrounding rock with dominant joint planes under impact disturbance and to further analyze the influence of different buried depths, impact stress wave peaks, and stress wave delays on the stability of the surrounding rock. The results show that the stability of the surrounding rock is poor, and the whole convergence deformation of the surrounding rock occurs under the impact stress wave. There are three failure modes in the surrounding rock: tensile-shear failure, tensile failure, and shear failure. Tensile-shear failure mainly occurs in a small range close to the roof and floor of the roadway and the free surfaces of the two sides, and tensile failure occurs locally, while shear failure mainly occurs along the joint plane outside this range. Moreover, the greater the buried depth and stress wave peak value, the more serious the deformation of the surrounding rock. With the increase of stress wave delay, the deformation of the surrounding rock shows complex characteristics. In addition, the impact failure mechanism of the surrounding rock in jointed rock masses was discussed. The research results have important guiding significance for the prevention and control of underground engineering cavern disasters.

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Research on the Matching of Impact Performance and Collision Coefficient of Hydraulic Rock Drill

Shock and Vibration ◽

10.1155/2021/6651860 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Yelin Li

Keyword(s):

Stress Wave ◽

Wave Model ◽

Wave Theory ◽

Collision Velocity ◽

Impact Performance ◽

Impact Stress ◽

Material Condition ◽

Rock Drill ◽

The Impact ◽

The Relationship

The stress wave produced by the piston impact, on the drill rod, is an important factor affecting impact performance. It is particularly important to control the stress waveform generated by the piston impact on the drill rod to meet the requirements of efficiency and component durability of some impact mechanical systems. Based on wave theory, the impact stress wave model of rock drilling is established, a dimensionless collision coefficient γ is put forward, and the matching relationship between different collision coefficients γ and stress waveforms is analysed. The length of the impact piston under the same material condition determines the change rule of the waveform. The stress waveform experimental verification is thus designed. The pressure chamber curves of different pistons in the rock drill were tested, the collision velocity of the piston was obtained, and the impact energy and impact power were calculated. The relationship between the impact performance and the collision coefficient γ is analysed. When γ is in the range of 9–11, the impact piston’s design of a high-power rock drill can be satisfied. When γ is in the range of 3∼5, it is mainly designed for low-power rock drills.

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Novel propagation behavior of impact stress wave in one-dimensional hollow spherical structures

International Journal of Impact Engineering ◽

10.1016/j.ijimpeng.2019.103368 ◽

2019 ◽

Vol 134 ◽

pp. 103368 ◽

Cited By ~ 2

Author(s):

Sha Yin ◽

Dianhao Chen ◽

Jun Xu

Keyword(s):

Stress Wave ◽

One Dimensional ◽

Impact Stress ◽

Propagation Behavior ◽

Spherical Structures ◽

Impact Stress Wave

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Design of the Power Unit in the Hydraulic Hybrid Vehicle

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.655-657.117 ◽

2013 ◽

Vol 655-657 ◽

pp. 117-122

Author(s):

Kai Yao ◽

Yang Li ◽

Ke Li Xing

Keyword(s):

Power Unit ◽

High Speed ◽

Large Diameter ◽

Hydraulic Pump ◽

Ansys Fluent ◽

Impact Stress ◽

Hydraulic Hybrid ◽

Hydraulic Hybrid Vehicle ◽

Simulation Results ◽

The Impact

In order to reduce the energy consumption and the hydraulic noise, the paper modifies the hydraulic pump/motor and designs a novel high-speed filling valve for the system, which is normally open and large-diameter. The modified pump/motor and the valve constitute the power unit. In the ANSYS/FLUENT the paper simulates numerically the flow field in the high-speed filling valve. By the use of ANSYS/LS-DYNA the paper analyzes the impact stress of the valve core. According to the simulation results, the power unit is optimized. Tests show that the noise decreases significantly in the vehicle utilizing the valve.

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