scholarly journals Experimental Research on the Mechanical Performance of the Bolted Rock under Lateral Impact Load: Effect of Prestress, Body Material, and Anchorage Style

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yongzheng Wu ◽  
Yukai Fu ◽  
Denyun Hao ◽  
Gangye Guo
Keyword(s):  
Axial Force ◽  
Impact Force ◽  
Impact Load ◽  
Impact Resistance ◽  
Time History ◽  
Full Length ◽  
Lateral Impact ◽  
Impact Peak ◽  
Action Time ◽  
The Impact

In order to reveal the impact mechanical properties and their key influencing factors of the bolted rock under the lateral impact load, through the lateral drop hammer impact test, the time-history curve of impact force, axial force of the bolt, and surface strain of the sample under different combination types of influencing factors is obtained, and the whole process of deformation and failure of the bolted rock is recorded. The test results show that the material of the bolt has a significant influence on the impact force and axial force of the bolt. There is a positive correlation between bolt strength and impact peak and impact attenuation slope and a negative correlation between bolt strength and impact action time. The effect of prestress on the impact resistance of the bolted rock was also evaluated by the test which suggested that prestress of the bolt can significantly reduce both impact time and bolt axial force of the bolted rock but has limited effect on the impact force. It was also found that the time-history curve of the impact force of anchoring rock mass had significant difference with full-length anchoring and nonanchoring. Compared with the nonanchoring bolt, the full-length anchored rock mass has a larger impact peak and shorter action time, which means that the impact resistance of the full-length bolted rock has a certain degree of weakening. Through scientific research, determining the reasonable bolt material, prestress value, and anchorage style can improve the impact resistance of the sample.

scholarly journals Study on the Impact Resistance of Metal Flexible Net to Rock fall

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Gaosheng Wang ◽  
Yunhou Sun ◽  
Ao Zhang ◽  
Lei Zheng ◽  
Yuzheng Lv ◽  
...  
Keyword(s):  
Finite Element ◽  
Impact Force ◽  
Impact Resistance ◽  
Time History ◽  
Rock Fall ◽  
Fe Model ◽  
Element Analysis ◽  
Inclination Angles ◽  
Fall Protection ◽  
The Impact

Based on experiments and finite element analysis, the impact resistance of metal flexible net was studied, which can provide reference for the application of metal flexible net in rock fall protection. The oblique (30 degrees) impact experiment of metal flexible net was carried out, the corresponding finite element (FE) to the experiment was established, and the FE model was verified by simulation results to the experimental tests from three aspects: the deformation characteristics of metal flexible net, the time history curves of impact force on supporting ropes, and the maximum instantaneous impact force on supporting ropes. The FE models of metal flexible nets with inclination angles of 0, 15, 30, 45, 60, and 75 degrees were established, and the impact resistance of metal flexible nets with different inclination angles was analyzed. The research shows that the metal flexible net with proper inclination can bounce the impact rock fall out of the safe area and prevent rock fall falling on the metal flexible net, thus realizing the self-cleaning function. When the inclination angle of the metal flexible net is 15, 30, and 45 degrees, respectively, the bounce effect after impact is better, the remaining height is improved, the protection width is improved obviously, and the impact force is reduced. Herein, the impact force of rock fall decreases most obviously at 45 degrees inclination, and the protective performance is relatively good.

Finite Element Analysis of a Single-Layer Reticulated Dome under Impact Loading

2010 ◽  
Vol 163-167 ◽  
pp. 327-331 ◽  
Author(s):  
Liang Zheng ◽  
Zhi Hua Chen
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Impact Force ◽  
Impact Load ◽  
Residual Deformation ◽  
Time History ◽  
Single Layer ◽  
Element Analysis ◽  
Deformation Stage ◽  
The Impact

Finite element model of both the single-layer Schwedler reticulated dome with the span of 50m and a Cuboid impactor were developed, incorporating ANSYS/LS-DYNA. PLASTIC_KINEMATIC (MAT_003) material model which takes stain rate into account was used to simulate steel under impact load. The automatic point to surface contact (NODES TO SURFACE) was applied between the dome and impact block. Three stages of time history curve of the impact force on the apex of the single-layer Scheduler reticulated dome including the impact stage, stable stalemate stage, the decaying stage were generalized according to its dynamic response. It must be pointed out that the peak of the impact force of the single-layer reticulated dome increase with the increase of the weight and the velocity of the impact block, but the change of the velocity of the impact block is more sensitive than the change of weight of the impact block for the effect of the peak of the impact force, and a platform value of the impact force of the single-layer reticulated dome change near a certain value, and the duration time of the impact gradually increase. Then four stages of time history curve of the impact displacement were proposed according to the dynamic response of impact on the apex of the single-layer reticulated dome based on numerical analysis. Four stages include in elastic deformation stage, plastic deformation stage, elastic rebound stage, free vibration stage in the position of the residual deformation.

scholarly journals Numerical simulation of GLARE 4A fiber-metal laminates subjected to ballistic impact

2018 ◽  
Vol 188 ◽  
pp. 01017
Author(s):  
George Bikakis ◽  
Nikolaos Tsigkros ◽  
Emilios Sideridis ◽  
Alexander Savaidis
Keyword(s):  
Impact Load ◽  
Impact Damage ◽  
Impact Resistance ◽  
Time History ◽  
Ballistic Impact ◽  
Fiber Metal Laminates ◽  
Ballistic Impacts ◽  
Fiber Metal ◽  
Force Time ◽  
The Impact

This article deals with the evaluation of the ballistic resistance of GLARE 4A fiber-metal laminates subjected to high velocity impact by a cylindrical projectile. Important impact variables such as the ballistic limit, the impact load and the absorbed energy time histories are predicted using the ANSYS LS-DYNA software. The simultaneous existence of various impact damage mechanisms, which is unique in fiber-metal laminates, is demonstrated using the numerical results. Each of the mechanisms absorbs a part of the initial impact energy and contributes to the high ballistic impact resistance the materials. With reference to the considered GLARE 4A panels, the behavior of the transient impact load is analyzed and useful conclusions are drawn. It is found that the maximum impact load is applied at the beginning of ballistic impacts, during the initial local indentation of the panels under the projectile. It is substantially higher than the following peak values of the impact force time history. It is revealed that during the beginning of ballistic impacts, the impulse of the collision increases as the thickness of the panels is increased. The work done by the impact load during the local indentation stage is also an increasing function of the panels’ thickness.

Study on the Impact Properties of a New Debris Flow Dam Based on Steel-Concrete Composite Structure

2014 ◽  
Vol 638-640 ◽  
pp. 2056-2059 ◽  
Author(s):  
Ya Xiong Liang ◽  
Xiu Li Wang ◽  
Chang Wu ◽  
Zhi Gang Lv
Keyword(s):  
Finite Element ◽  
Debris Flow ◽  
Impact Force ◽  
Impact Load ◽  
Weak Link ◽  
Time History ◽  
Type Model ◽  
Finite Element Software ◽  
New Type ◽  
The Impact

The impact force is one of the most weak link of the dynamics studies of debris flow for many years. To make the structure or components are better able to suffer the impact load such as debris flow, explosions, a new debris flow dam is designed by introducing this new type model with spring. It is simulated under boulder impact by using finite element software LS-DYNA.The stress distribution, impact and displacement time history curve under typical conditions are obtained. The results show that the resist impact effect of new debris flow dam is very obvious.

Study on Concrete Filled Square Steel Tube under Lateral Impact Loading

2010 ◽  
Vol 163-167 ◽  
pp. 941-946
Author(s):  
Liang Zheng ◽  
Zhi Hua Chen
Keyword(s):  
Dynamic Response ◽  
Impact Force ◽  
Residual Deformation ◽  
Time History ◽  
Steel Tube ◽  
Lateral Impact ◽  
Deformation Stage ◽  
Elastic Rebound ◽  
Square Steel Tube ◽  
The Impact

Finite element models of both the concrete filled square steel tube and a Cuboid impactor were developed, incorporating ANSYS/LS-DYNA. Three stages of time history curve of the impact force of the concrete filled square steel tube including the impact stage, stable stalemate stage, the decaying stage were generalized according to its dynamic response. And with the wall thickness increased, the peak of the impact force and the platform value is also increase, with axial force increased, the peak impact force hardly changed, but the impact platform value have a certain extent lower. Then four stages of time history curve of the impact displacement were proposed according to the dynamic response of the impact of the concrete filled square steel tube based on numerical analysis, four stages include in elastic deformation stage, plastic deformation stage, elastic rebound stage, free vibration stage in the position of the residual deformation. Finally, time history curve of the impact force and displacement according to the dynamic response is analyzed under the impact of the corner of the concrete filled square steel tube, the results show that the anti-impact capability of 45 degree angle is higher than that of the front impact.

scholarly journals Experimental and numerical study of axially-loaded RC columns and frame columns under lateral impact loading

2021 ◽  
Author(s):  
Zheng Luo ◽  
Wang Yinhui
Keyword(s):  
Impact Load ◽  
Numerical Study ◽  
Impact Resistance ◽  
Impact Excitation ◽  
Lateral Impact ◽  
Axial Loads ◽  
Free Standing ◽  
Positive Role ◽  
The Moment ◽  
The Impact

The pendulum impact tests were carried out on one RC frame column and four RC free-standing columns. The effect of axial compression ratio and reinforcement ratio on the impact resistance of columns were compared by means of dynamic time curves of framed and freestanding columns under impact. The test results show that with the same impact load, though the presence of axial loads can play a positive role (e.g., reducing the residual displacement), it may lead to more severe local damage. Also, compared with free-standing columns, the frame column can be considered as a protective structure for its greater lateral stiffness and stronger crashworthiness. The corresponding finite element models are developed，and the influence of the axial loads on cross section force responses under impact excitation is deeply explored. The axial loads can significantly affect the distribution of the moment, the shear force, and also the damage for the column.

Lateral Impact Response of Elliptical Hollow and Partially Concrete-Filled Cold-Formed Steel Columns Under Static Axial Compression Load

2021 ◽  
Author(s):  
Nayyer Mohammadi Rana ◽  
Elham Ghandi ◽  
Shirin Esmaeili Niari
Keyword(s):  
Impact Velocity ◽  
Impact Load ◽  
Impact Resistance ◽  
Compressive Load ◽  
Lateral Impact ◽  
Elliptical Cross ◽  
Compression Load ◽  
Steel Columns ◽  
Size And Shape ◽  
The Impact

In recent years, the use of partially concrete-filled steel tubular (PCFST) columns has been considered due to their cost-effectiveness and reduction of structural weight in bridge piers and building columns. One of the critical discussions about these columns is their impact resistance. In this article, the dynamic response of hollow and PCFST columns with elliptical cross-section under simultaneous loading of static axial compressive load and lateral impact load is presented using finite element modeling in ABAQUS software (FEA). To ensure the accuracy of the numerical modeling, the analysis results are compared with the results of previous works. The effects of different parameters such as impact velocity, the height of the impact location, the impact direction, the impact block mass, the size and shape of the impact block are investigated in this paper. The results of the numerical analysis showed that the partially filled specimens had better performance than the hollow specimens. The changes in impact direction and impact block mass parameters have a significant effect on the failure of the columns, especially when they are under high impact velocity. Changing the impact velocity significantly affects the impact resistance of specimens. However, the size and shape of the impact block did not have a significant effect on the displacement of the column against the impact loading.

Numerical Modeling of Reinforced Concrete Slabs under Impact Loading

2020 ◽  
Vol 857 ◽  
pp. 99-108
Author(s):  
Enas Mabrook Mouwainea ◽  
Abdul Muttalib I. Said
Keyword(s):  
Reinforced Concrete ◽  
Impact Force ◽  
Impact Load ◽  
Time History ◽  
Reinforcement Ratio ◽  
Concrete Slabs ◽  
Slab Thickness ◽  
Central Deflection ◽  
Reinforced Concrete Slabs ◽  
The Impact

This paper aims to provide a numerical model able to represent the behavior of reinforced concrete slabs subjected to impact loads. The nonlinear finite element analysis adopted by ABAQUS/Explicit Software was used in this study. A parametric study was conducted to provide a comprehensive understanding of the behavior of reinforced concrete slabs subjected to impact load. Two parameters were varied amongst the slabs which classified in to two groups. In the first groups, the thickness of slabs is variable, which was equal to (75, 100, 150 mm). In the second group, the thickness of the slab is constant and the variable was the reinforcement ratio, which ranged from (0.58 to 1%), per layer. In dynamic analysis, the load-time history and deflection-time relation were investigated. For the first group, obviously, as the slab thickness increased, the maximum central deflection of the slabs decreased by (48 – 84 %). Also, the impact force of the slabs increased by (40 – 106%) as the thickness of the slab increased by (33 – 100%). For the second group, the maximum central deflection of the slabs decreased by (6.6 – 8.8 %) as the steel reinforcement increased by (0.58 – 1 %). It was observed in the second group that the change in the value of the impact force was very limited. This lead to a fact that the impact force was not affected by the change of the reinforcement ratio, but mainly affected by the change of the slab thickness.

scholarly journals Deflection Calculation Based on SDOF Method for Axially Loaded Concrete-Filled Steel Tubular Members Subjected to Lateral Impact

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Luming Wang ◽  
Yanhui Liu ◽  
Jiahuan Song ◽  
Shichun Zhao ◽  
Zhe Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Axial Force ◽  
Calculation Method ◽  
Axial Load ◽  
Impact Force ◽  
Great Influence ◽  
Lateral Impact ◽  
Simulation Accuracy ◽  
Axially Loaded ◽  
The Impact

Axial force has a great influence on the dynamic behavior and the impact resistance of concrete-filled steel tubular (CFST) members. Based on numerical simulation and theoretical analysis, the impact response and deflection calculation method for axially loaded CFST members subjected to lateral impact are investigated in this paper. The nonlinear numerical model of an axially loaded CFST member considering the strain rate effects has been established, and the simulation accuracy has been validated by comparing with existing test results. The contrastive investigation is carried out to illustrate the influence of axial load on the variation pattern of impact force for CFST members under various structural and impact parameters, and its result indicates that the impact force-time histories for CFST members with different axial loads are mainly characterized by rectangular pulse and triangular pulse. Moreover, a simplified calculation method considering the effect of axial force is proposed based on the equivalent single degree of freedom (SDOF) method, devoted to predicting the deflection of axially loaded CFST members subjected to lateral impact. The comparisons with the numerical simulation prove that the deflection calculation method has a reasonable accuracy; thus, the proposed method can be utilized in the damage assessment and anti-impact design for CFST members subjected to lateral impact and axial load.

scholarly journals Sandwich panel with in-plane honeycombs in different Poisson's ratio under low to medium impact loads

2021 ◽  
Vol 60 (1) ◽  
pp. 145-157
Author(s):  
Yi Luo ◽  
Ke Yuan ◽  
Lumin Shen ◽  
Jiefu Liu
Keyword(s):  
Poisson’S Ratio ◽  
Sandwich Panel ◽  
Impact Force ◽  
Impact Resistance ◽  
Poisson's Ratio ◽  
Compression Performance ◽  
Post Impact ◽  
Local Impact ◽  
Collapse Behavior ◽  
The Impact

Abstract In this study, a series of in-plane hexagonal honeycombs with different Poisson's ratio induced by topological diversity are studied, considering re-entrant, semi-re-entrant and convex cells, respectively. The crushing strength of honeycomb in terms of Poisson's ratio is firstly presented. In the previous research, we have studied the compression performance of honeycomb with different negative Poisson's ratio. In this study, a comparative study on the local impact resistance of different sandwich panels is conducted by considering a spherical projectile with low to medium impact speed. Some critical criteria (i.e. local indentation profile, global deflection, impact force and energy absorption) are adopted to analyze the impact resistance. Finally, an influential mechanism of Poisson's ratio on the local impact resistance of sandwich panel is studied by considering the variation of core strength and post-impact collapse behavior.

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