scholarly journals Analysis of Dynamic Response Behavior of Crack under Impact Stress Wave

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1920
Author(s):  
Yan Peng ◽  
Yang Liu ◽  
Wei Zhang
Keyword(s):  
Fracture Mechanics ◽  
Dynamic Response ◽  
Stress Wave ◽  
Dynamic Fracture ◽  
Impact Load ◽  
Stress Wave Propagation ◽  
Failure Behavior ◽  
Stress And Strain ◽  
Response Behavior ◽  
Shock Stress

The structural parts of construction machinery mostly fail due to impact load, but current research on the failure behavior of the impact load has not established a complete theoretical system. Based on wave theory and fracture mechanics, this paper analyzed the wave behavior of shock stress waves and established a model of shock stress wave propagation. Given the dynamic response behavior of the stress and strain field at the crack tip, dynamic fracture mechanics theory was used to solve the dynamic fracture strength stress factor and evaluate the dynamic fracture performance of the structure with crack damage under shock waves. Through dynamic response analysis and numerical calculation of the typical SHPB (split Hopkinson pressure bar) test standard compact tension (CT) specimens under the short-term strong shock stress wave, the stress and strain evolution law of the material under the shock wave was analyzed, and the correlation of the shock stress wave was verified. This research work can meet the requirements of engineering design and has practical engineering significance, playing an important role in material safety design.

Numerical Investigation of the Stress Wave Propagation in the Incident Bar and the Specimen

2014 ◽  
Vol 602-605 ◽  
pp. 98-101 ◽  
Author(s):  
Raja Ahsan Javed ◽  
Shi Fan Zhu ◽  
Chun Huan Guo ◽  
Feng Chun Jiang
Keyword(s):  
Stress Wave ◽  
Dynamic Fracture ◽  
Sine Wave ◽  
Stress Wave Propagation ◽  
Stress And Strain ◽  
Hopkinson Pressure Bar ◽  
Time Duration ◽  
Fracture Properties ◽  
Propagation Behavior ◽  
Pressure Bar

Hopkinson pressure bar apparatus is extensively used for the measurement of the dynamic fracture properties. For accurate measurement of the dynamic fracture properties we need to understand concepts and principles associated with the test setup. The understanding of stress wave in the bar and specimen is also very important. In the current work, ANSYS LS-DYNA software is used to simulate the propagation behavior of the time based loading and generation of stress wave. The stress and strain plots in the specimen and the incident bar are obtained as an output of the analysis. The analysis of the plots suggest that, for the same time duration the rising trend is observed for the plots of stress and strain of incident bar whereas a sine wave trend is observed for the plots in the specimen.

Research on Attenuation of Shock Induced Stress Wave in Multi-Layered Thin Cylindrical Rods

2018 ◽  
Vol 878 ◽  
pp. 35-40
Author(s):  
Fei Peng ◽  
Zhi Guang Yang ◽  
Li Peng Wang
Keyword(s):  
Stress Wave ◽  
Wave Attenuation ◽  
Impact Load ◽  
Layered Media ◽  
One Dimension ◽  
Stress Wave Propagation ◽  
Propagation Theory ◽  
Induced Stress ◽  
The One ◽  
Wave Induced

The attenuation of stress wave induced by impact load in multi-layered thin cylindrical rods has been investigated and analyzed. Firstly, based on stress wave propagation theory, the one dimension solution of the response of stress wave in three-layered media has been given. Secondly, a three-layered thin cylindrical rod has been established through FEM, and the propagation and attenuation of stress wave in it has been analyzed. The analytical and numerical results showed that the stress wave attenuation could be achieved by using multi-layered media.

Analyzing Stress Wave Propagation in a Hollow Bar Loaded Three-Point Bend Fracture Test Using Numerical Methods

2015 ◽  
Vol 782 ◽  
pp. 252-260 ◽  
Author(s):  
Raja Ahsan Javed ◽  
Shi Fan Zhu ◽  
Chun Huan Guo ◽  
Feng Chun Jiang
Keyword(s):  
Wave Propagation ◽  
Stress Wave ◽  
Crack Tip ◽  
Small Sample ◽  
Stress Wave Propagation ◽  
Stress And Strain ◽  
Bend Specimen ◽  
Transient Time ◽  
Propagation Behavior ◽  
Point Bend

Modified Hopkinson pressure bar apparatus is widely used to investigate the dynamic fracture behavior of materials at higher rate loading. While using a small sample for fracture toughness testing, plane strain conditions are compromised. In the current work, a large diameter two-bar/ three-point bend fracture setup is used to analyze stress wave propagation behavior within a larger cracked specimen. The experimental setup model consists of striker, incident bar, loading pin, cracked three-point specimen, span and transmission bar. The model is prepared using ANSYS software and the transient dynamic analysis technique is used to simulate the dynamic load. The effects of increased transient time on the stress wave propagation behavior within the cracked sample and the stress and strain values at the crack tip of the three-point bend specimen are analyzed. In addition, the effects of the hollow striker, the hollow incident bar and the specimen span are studied. It is found that during large specimen testing, an increase in the transient time results in the lower stress and strain values in the specimen crack-tip. The relationship of the specimen span, the striker and the incident bars with the strain values in the specimen is analyzed and a method for the three-point bend specimen testing at the higher strain rates is also proposed.

Hopkinson Bar Loaded Fracture Experimental Technique: A Critical Review of Dynamic Fracture Toughness Tests

2009 ◽  
Vol 62 (6) ◽  
Author(s):  
Fengchun Jiang ◽  
Kenneth S. Vecchio
Keyword(s):  
Fracture Toughness ◽  
Stress Wave ◽  
Dynamic Fracture ◽  
Fracture Behavior ◽  
Hopkinson Bar ◽  
Dynamic Fracture Toughness ◽  
Stress Wave Propagation ◽  
Theoretical Formula ◽  
Wave Loading ◽  
Engineering Materials

Hopkinson bar experimental techniques have been extensively employed to investigate the mechanical response and fracture behavior of engineering materials under high rate loading. Among these applications, the study of the dynamic fracture behavior of materials at stress-wave loading conditions (corresponding stress-intensity factor rate ∼106 MPam/s) has been an active research area in recent years. Various Hopkinson bar loading configurations and corresponding experimental methods have been proposed to date for measuring dynamic fracture toughness and investigating fracture mechanisms of engineering materials. In this paper, advances in Hopkinson bar loaded dynamic fracture techniques over the past 30 years, focused on dynamic fracture toughness measurement, are presented. Various aspects of Hopkinson bar fracture testing are reviewed, including (a) the analysis of advantages and disadvantages of loading systems and sample configurations; (b) a discussion of operating principles for determining dynamic load and sample displacement in different loading configurations; (c) a comparison of various methods used for determining dynamic fracture parameters (load, displacement, fracture time, and fracture toughness), such as theoretical formula, optical gauges, and strain gauges; and (d) an update of modeling and simulation of loading configurations. Fundamental issues associated with stress-wave loading, such as stress-wave propagation along the elastic bars and in the sample, stress-state equilibrium validation, incident pulse-shaping effect, and the “loss-of-contact” phenomenon are also addressed in this review.

Numerical Simulation of Square Steel Tube Beam Filled with Steel-Reinforced High-Strength Concrete Dynamic Response under Impact Load

2011 ◽  
Vol 94-96 ◽  
pp. 2084-2087 ◽  
Author(s):  
Shun Bo Li ◽  
Jun Yang ◽  
Chen Xi Xia ◽  
Da Yong Chen
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
High Strength Concrete ◽  
Impact Load ◽  
High Strength ◽  
Steel Tube ◽  
Stress Wave Propagation ◽  
Strength Concrete ◽  
Combined Action ◽  
Square Steel Tube

Using ANSYS / LS-DYNA to study the dynamic response of square steel tube beam filled with steel-reinforced high-strength concrete under impact loading at different speeds. The numerical simulation results show that: At different conditions of speed, the concrete failure modes are different. The combined action of Steel tube and steel flange makes the stress wave propagation extremely complex in the beam, when the speed increased to a certain value, it made damage to the internal steel flange and flange lateral concrete under impact load, while the concrete between the top of steel flange and steel tube was protected by the combined action.

scholarly journals Stress Wave Propagation and Energy Absorption Properties of Heterogeneous Lattice Materials under Impact Load

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Cun Zhao ◽  
Meng Zhang ◽  
Guoxi Li ◽  
Dong Wang
Keyword(s):  
Wave Propagation ◽  
Energy Absorption ◽  
Stress Wave ◽  
Impact Load ◽  
Absorption Capacity ◽  
Stress Wave Propagation ◽  
Absorption Properties ◽  
Lattice Materials ◽  
Lattice Material ◽  
Heterogeneous Lattice

A heterogeneous lattice material composed of different cells is proposed to improve the energy absorption capacity. The heterogeneous structure is formed by setting layers of body-centered XY rods (BCCxy) cells as the reinforcement in the body-centered cubic (GBCC) uniform lattice material. The heterogeneous lattice samples are designed and processed by additive manufacturing technology. The stress wave propagation and energy absorption properties of heterogeneous lattice materials under impact load are analyzed by finite element simulation (FES) and Hopkinson pressure bar (SHPB) experiments. The results show that, compared with the GBCC uniform lattice material, the spreading velocity of the stress of the (GBCC)3(BCCxy)2 heterogeneous lattice material is reduced by 18.1%, the impact time is prolonged 27.9%, the stress peak of the transmitted bar is reduced by 34.8%, and the strain energy peak is reduced by 29.7%. It indicates that the heterogeneous lattice materials are able to reduce the spreading velocity of stress and improve the energy absorption capacity. In addition, the number of layers of reinforcement is an important factor affecting the stress wave propagation and energy absorption properties.

scholarly journals Effects of External Dynamic Disturbances And Structural Plane On Rock Fracturing Around Deep Underground Cavern

2021 ◽  
Author(s):  
Fan Feng ◽  
Shaojie Chen ◽  
Xingdong Zhao ◽  
Diyuan Li ◽  
Xianlai Wang ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Stress Wave ◽  
Failure Behavior ◽  
Dynamic Disturbance ◽  
Structural Plane ◽  
Crack Distribution ◽  
Underground Cavern ◽  
Geological Conditions ◽  
Failure Intensity ◽  
Geological Discontinuities

Abstract The occurrence of disasters in deep mining engineering has been confirmed to be closely related to the external dynamic disturbances and geological discontinuities. Thus, a combined finite-element approach was employed to simulate the failure process of an underground cavern, which provided insights into the failure mechanism of deep hard rock affected by factors such as the dynamic stress-wave amplitudes, disturbance direction, and dip angles of the structural plane. The crack-propagation process, stress-field distribution, displacement, velocity of failed rock, and failure zone around the circular cavern were analyzed to identify the dynamic response and failure properties of the underground structures. The simulation results indicated that the dynamic disturbance direction had less influence on the dynamic response for the constant in situ stress state, while the failure intensity and damage range around the cavern always exhibited a monotonically increasing trend with an increase in the dynamic load (stress-wave amplitudes). The crack distribution around the circular cavern exhibited an asymmetric pattern, possibly owing to the stress-wave reflection behavior and attenuation effect along the propagation route. Geological discontinuities significantly affected the stability of nearby caverns subjected to dynamic disturbances, during which the failure intensity exhibited the pattern of an initial increase followed by a decrease with an increase in the dip angle of the structural plane. Additionally, the dynamic disturbance direction led to variations in the crack distribution for specific structural planes and stress states. These results indicate that the failure behavior should be the integrated response of the excavation unloading effect, geological conditions, and external dynamic disturbances.

The Effect of Stress Wave on Dynamic Response of Square Thin-Walled Tube

2014 ◽  
Vol 590 ◽  
pp. 63-68 ◽  
Author(s):  
Zhu Hua Tan ◽  
Bo Zhang ◽  
Peng Cheng Zhai
Keyword(s):  
Wave Propagation ◽  
Dynamic Response ◽  
Stress Wave ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Stress Wave Propagation ◽  
Hopkinson Pressure Bar ◽  
Thin Walled Tube ◽  
Split Hopkinson ◽  
Pressure Bar

The effect of stress wave propagation on dynamic response of square tube was investigated by the experimental and numerical simulation methods in the present paper. The square tubes were subjected to the axial impact by split Hopkinson pressure bar. And the deformation process of each square tube was recorded by a high speed camera. Typical dynamic plastic buckling phenomena were observed in the experiments. And the numerical calculation of the experimental load case was conducted to analyze the effect of the stress wave propagation on the initial buckling of the square tube. The results show that there is obvious stress wave propagation in the square tube before the buckling of the square tube. And the initial buckling starts from the rear end of the tube due to the propagation of the stress wave. The relation between the stress wave propagation and initial buckling of the square tube was also discussed.

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