Analysis and Numerical Simulation on Dynamic Response of Buried Pipeline Caused by Rock Fall Impaction

2012 ◽  
Author(s):  
Hongyuan Jing ◽  
Qinglu Deng ◽  
Jianbin Hao ◽  
Bing Han ◽  
Liangliang Li
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
Cross Section ◽  
Impact Force ◽  
Equivalent Stress ◽  
Rock Fall ◽  
Major Influence ◽  
Buried Pipeline ◽  
Stress Concentration Region ◽  
The Impact

Theoretical analysis methods are discussed to estimate additional stresses of shallow buried oil and gas pipeline caused by rock fall impaction. The process of impaction is simulated using finite elements software, in the model a 1 m3 square shape falling hard rock impacts soil ground upright of pipe with a vertical velocity, and dynamic response of pipeline is analyzed. The impact force, soil additional stresses, pipe displacement and additional stresses in the impaction process are studied. The effect of pipeline buried depth and rock velocity to the impaction also discussed. Results show that the impaction process is very short and the duration is about 10−3∼10−2s. The maximum impact force has approximately direct ratio with the velocity of rock. The additional vertical stress in soil caused by impaction load has a stress concentration region near the surface of pipe, and its distribution has the similar pattern with that in static load, but has a faster attenuation from the impaction center to sidewall. The most dangerous pipe cross-section appears in the underside of impaction center, and the maximum additional equivalent stress appears in the top of the cross-section, and has an approximately direct ratio with the velocity of rock if other impaction conditions are confirmed. The buried depth of pipeline has major influence to impaction. Large thickness of soil cover has marked effect on improve the protection of pipeline. According the study, shallow buried pipeline has weak defense to rock fall. The additional internal force and stress of pipeline caused by impaction of rock fall can be approximately estimated using theoretical methods or numerical simulation.

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.

Dynamic Response and Shear Demand of Reinforced Concrete Beams Subjected to Impact Loading

2019 ◽  
Vol 19 (08) ◽  
pp. 1950091 ◽  
Author(s):  
Wuchao Zhao ◽  
Jiang Qian
Keyword(s):  
Dynamic Response ◽  
Impact Loading ◽  
Parametric Study ◽  
Shear Failure ◽  
Impact Force ◽  
Rc Beams ◽  
Local Response ◽  
Shear Demand ◽  
The Impact ◽  
Peak Impact Force

Reinforced concrete (RC) beams under the impact loading are typically prone to suffer shear failure in the local response phase. In order to enhance the understanding of the mechanical behavior of the RC beams, their dynamic response and shear demand are numerically investigated in this paper. A 3D finite-element model is developed and validated against the experimental data available in the literature. Taking advantage of the above calibrated numerical model, an intensive parametric study is performed to identify the effect of different factors including the impact velocity, impact mass and beam span-to-depth ratio on the impact response of the RC beams. It is found that, due to the inertial effect, a linear relationship exists between the maximum reverse support force and the peak impact force, while negative bending moments also appear in the shear span. In addition, the local response of the RC beams can be divided into a first impact stage and a separation stage. A shear plug is likely to be formed near the impact point at the first impact stage and a shear failure may be triggered near the support by large support forces. Based on the simulation results, simplified methods are proposed for predicting the shear demand for the two failure modes, whereas physical models are also established to illustrate the resistance mechanism of the RC beams at the peak impact force. By comparing with the results of the parametric study, it is concluded that the shear demand of the RC beams under the impact loading can be predicted by the proposed empirical formulas with reasonable accuracy.

Vibration Analysis of Different Micro-Beams with Laser Ablation

2013 ◽  
Vol 462-463 ◽  
pp. 428-431
Author(s):  
Liang Cai Xiong ◽  
Quan Sheng Zhou ◽  
Peng Chen
Keyword(s):  
Laser Ablation ◽  
Dynamic Response ◽  
Vibration Analysis ◽  
Laser Excitation ◽  
Impact Force ◽  
Laser Doppler Vibrometer ◽  
Impact Response ◽  
Vibration Velocity ◽  
Laser Shock ◽  
The Impact

The dynamic response of different micro-beams after laser excitation experiments have been investigated in this paper. The impact force that induces the vibration of micro-beams is the interaction of focused pulse laser and tested beams. The impact response of micro-beams after being excited is measured by Laser Doppler Vibrometer. Different beams such as cantilever beam, L-shaped beam are employed in our experiments. Comparisons of the vibration velocity and its frequencies of different beams have also been performed. Experimental results show that the mechanical effects of laser shock do really exist and can be utilized.

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.

Numerical Simulation and Experimental Study on Fluid-Filled Hemispherical Shell under Impact

2013 ◽  
Vol 364 ◽  
pp. 172-176
Author(s):  
Hui Wei Yang ◽  
Bin Qin ◽  
Zhi Jun Han ◽  
Guo Yun Lu
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
Impact Load ◽  
Elastic Recovery ◽  
Plastic Hinge ◽  
Time History ◽  
Hemispherical Shell ◽  
History Of ◽  
Local Impact ◽  
The Impact

The dynamic response of fluid-filled hemispherical shell in mass impact is studied by experiment using DHR9401. Combining the time history of impact force with experimental observation of the deformation process, it can be seen that the dynamic response can be divided into four stages: the flattening around the impact point, the forming and expanding outward of shell plastic hinge, the plastic edge region flatten by the punch, and elastic recovery. The experimental results show that: Because the shell filled with liquid, the local impact load that the shell suffered is translated into area load and loads on the inner shell uniformly, so that it has a high carrying capacity. Numerical simulation is used to study the time history of energy absorption of different shell structures. The result shows that the crashworthiness of sandwich fluid-filled shell is improved greatly. Under the certain impact energy, deformation of its inner shell is very small, which can provide effective security space.

Dynamic Response Analysis of Control Rod Drive Mechanism Under the Stepping Impact Force for Nuclear Power Plants

2012 ◽  
Author(s):  
Xiaoyao Shen ◽  
Yongcheng Xie
Keyword(s):  
Dynamic Response ◽  
Nuclear Power ◽  
Power Plants ◽  
Structural Integrity ◽  
Impact Force ◽  
Response Analysis ◽  
Control Rod ◽  
Drive Mechanism ◽  
Finite Element Software ◽  
The Impact

The control rod drive mechanism (CRDM) is an important safety-related component in the nuclear power plant (NPP). When CRDM steps upward or downward, the pressure-containing housing of CRDM is shocked axially by an impact force from the engagement of the magnetic pole and the armature. To ensure the structural integrity of the primary coolant loop and the functionality of CRDM, dynamic response of CRDM under the impact force should be studied. In this manuscript, the commercial finite element software ANSYS is chosen to analyze the nonlinear impact problem. A nonlinear model is setup in ANSYS, including main CRDM parts such as the control rod, poles and armatures, as well as nonlinear gaps. The transient analysis method is adopted to calculate CRDM dynamic response when it steps upward. The impact loads and displacements at typical CRDM locations are successfully obtained, which are essential for design and stress analysis of CRDM.

A comparative study on the behaviour of free-fall lifeboat launching from a skid and from a hook

2000 ◽  
Vol 214 (2) ◽  
pp. 359-370 ◽  
Author(s):  
M Reaz H Khondoker ◽  
M Arai
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
Comparative Study ◽  
Impact Force ◽  
Free Fall ◽  
Water Entry ◽  
Hydrodynamic Forces ◽  
Response Criteria ◽  
Risk Of Injury ◽  
Tremendous Impact

There are two commonly used launching methods of free-fall lifeboats: from a skid and from a hook. A free-fall lifeboat, whether it is released from a skid or from a hook, experiences tremendous impact when it enters the water. This impact force, together with other hydrostatic and hydrodynamic forces and moments, affects the motions and accelerations of the boat considerably. In this paper, a comparative study on the behaviours of the skid and hook launching of free-fall lifeboats has been presented. Numerical simulation for different launching methods has been used as a tool to obtain trajectories of the lifeboat for different launching conditions. Also polar diagrams of accelerations are drawn using the data computed for the same conditions. Dynamic response criteria have been used in order to evaluate the risk of injury to the occupants during water entry of the lifeboat.

Numerical Simulation Analysis of Collision between Ship and Steel Sheet Pile Quay-Wall

2015 ◽  
Vol 744-746 ◽  
pp. 1175-1179 ◽  
Author(s):  
Peng Liu ◽  
Hong Wang ◽  
Chao Zhu
Keyword(s):  
Numerical Simulation ◽  
Steel Sheet ◽  
Impact Force ◽  
Simulation Analysis ◽  
Sheet Pile ◽  
Time Curve ◽  
Finite Element Software ◽  
Quay Wall ◽  
Force Time ◽  
The Impact

The impact process of 50000t ship and steel sheet pile bulkhead is simulated by finite element software ANSYS/LS-DYNA. This article acquires the impact force-time curve, equivalent force-time curve of steel sheet pile and the pressure-time curve of breast wall. Comparing the impact force of numerical simulation with the result of ship-bridge collision specifications, and general rules and characteristics are obtained. At the same time, put forward some measures to prevent the damage of wharf structure under the ship of large velocity impact, which provide theoretical references during the design, maintenance, and transformation of similar wharf.

scholarly journals An analytical model to determine the impact force of drone strikes

2021 ◽  
Author(s):  
Florian Franke ◽  
Michael Schwab ◽  
Uli Burger ◽  
Christian Hühne
Keyword(s):  
Load Distribution ◽  
Impact Force ◽  
Analytical Calculation ◽  
Calculation Model ◽  
Material Behavior ◽  
Major Influence ◽  
Impact Model ◽  
Simulation Data ◽  
Input Parameters ◽  
The Impact

AbstractIn addition to the well-known threats of bird and hail strikes, small unmanned aerial vehicles (sUAV) pose a new threat to manned aviation. Determining the severity of collisions between sUAVs and aircraft structures is essential for the safe use and integration of drones in airspace. A generic analytical calculation model needs to be developed to supplement the existing test and simulation data. This paper presents an analytic model for drone collisions with perpendicular and inclined targets. The targets have a rigid or elastic material behavior. The aircraft impact model, which is used for the design of nuclear reactor structures, is transferred and adjusted for sUAV impacts to calculate the impact force. A mass- and a burst load distribution are needed as input parameters. Both distributions are determined for an sUAV design depending on the flight direction. Compared to previous calculations, the new approach is to consider a moving target structure, which produces more realistic results. We compare the calculation results with simulation data from sUAV collisions with a commercial airliner windshield from the literature. The calculations show plausible results and a good agreement with literature data. Subsequently, the influence of the input parameters on the impact force is investigated. We see that spring stiffness, target mass, burst load distribution and damping have minor influence on the overall impact force. The impact velocity, mass distribution and flight orientation on the other hand have a major influence on the impact force. Further tests are needed to validate the impact model.

Sign in / Sign up

Export Citation Format

Share Document