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.

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

2012 ◽  
Vol 594-597 ◽  
pp. 844-848
Author(s):  
Liang Zheng
Keyword(s):  
Finite Element ◽  
Impact Loading ◽  
Impact Force ◽  
Numerical Models ◽  
Time History ◽  
Single Layer ◽  
Impact Response ◽  
Element Analysis ◽  
Peak Displacement ◽  
The Impact

This paper treats the impact force and the displacement of the lamella single-layer reticulated dome and the suspendome under axial impact loading using non-linear finite element techniques. The influence of loading parameters and the cable force of the suspendome on the impact response is investigated using validated numerical models. Results are quantified in terms of important impact response parameters and indicate that the peak displacement of the lamella single-layer reticulated dome and the suspendome can be clearly divided into four stages with time , and time history curve of the impact force can be divided into three stages.

scholarly journals Design and analysis of demolition robot arm based on finite element method

2019 ◽  
Vol 11 (6) ◽  
pp. 168781401985396 ◽  
Author(s):  
Jiong Li ◽  
Yu Wang ◽  
Kai Zhang ◽  
Zhiqiao Wang ◽  
Jiaxing Lu
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Impact Force ◽  
Second Order ◽  
Robot Arm ◽  
Element Analysis ◽  
Front End ◽  
The Finite Element Analysis ◽  
The Impact ◽  
Ansys Workbench

As a novel robot which mainly engages in the demolition and transformation of various concrete buildings, the demolition robot has developed rapidly in recent years. The impact force is mainly produced by the breaking hammer installed in the front end of the arm. As the most important part of a demolition robot, the boom arm is mainly composed of four parts including a supporting arm, a main arm, a fore arm, and a breaking hammer system. In this article, a mechanical model of the boom arm is established, and the finite element analysis obtaining the first four-order natural frequencies and modes is carried out in ANSYS Workbench. The results reveal that the resonation can be easily stimulated when a hydraulic breaking hammer is at the second-order frequency. The mounting block of the hydraulic breaking hammer, the hinge parts of the supporting arm, and the main arm are easily deformed or damaged in the Y direction by analyzing the deformation in three directions of the second-order mode. After the structure optimization, the vibration characteristics of the two parts are significantly enhanced, which provides a theoretical basis for optimizing the prototype and gives a reference in the experimental modes.

Concrete LNG GBS Terminal Ship Collision Study

2008 ◽  
Author(s):  
Fuqiang Wu ◽  
Frank Puskar ◽  
Pascinthe Saad
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Integrity ◽  
Impact Resistance ◽  
Liquefied Natural Gas ◽  
Element Analysis ◽  
Benchmark Tests ◽  
Ship Collision ◽  
Numerical Tool ◽  
The Impact

Concrete Gravity Based Structure (GBS) provides an opportunity for the storage of Liquefied Natural Gas (LNG) and represents one of the key elements of an LNG receiving and regasification terminal. The impact resistance of an offshore LNG GBS against accidental ship collision needs to be evaluated. Nonlinear elasto-plastic Finite Element Analysis (FEA) provides a useful numerical tool to assess the damage and evaluate the overall structural integrity of the GBS following a ship collision. In the work presented, a large capacity tanker was modeled using FEA and simulated to collide into a prototype concrete LNG GBS. An efficient, two-step approach was applied to estimate the damage levels caused by the striking tanker considering different approach speeds. Various benchmark tests were conducted to validate the steel and concrete FEA models to ensure the reliability of the analysis. The simulation shows that certain collisions can cause damage to both the tanker bow and the LNG GBS, depending upon the collision speed and the configuration of the colliding bodies. However, these collisions do not always result in a breach of the LNG containment. The results of this type of assessment can be used to assist in designing the LNG GBS to improve its impact resistance. The results can also be used in risk studies typical of these types of facilities.

EFFECT OF THE FLUID ON THE IMPACT FORCE OF THE WET MISSILE

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Duc-Kien Thai ◽  
Seung-Eock Kim
Keyword(s):  
Impact Force ◽  
Force Plate ◽  
Time History ◽  
Research Centre ◽  
Element Analysis ◽  
Time Histories ◽  
Target Wall ◽  
Force Time ◽  
Missile Test ◽  
The Impact

In this paper, the force-time histories of soft missiles, with and without filled water, impacting the target wall were investigated using finite element analysis. The force plate tests, with a dry missile (test FP8) and a wet missile (test FP16) carried out by Technical Research Centre of Finland (VTT), were used. The numerical analysis results were verified by comparing with those of experiments. A parametric analysis with different missile velocities was also performed to investigate the force-time history and impulse of the missile impact on target plate. Based on a comparison with the Riera approach, the coefficients were proposed to modify the Riera function. The analysis results show that, the Riera function accurately predicted the impact force time history in the case of the dry missile. However, in the case of the wet missile, the coefficients α from 1.24 to 1.45 are recommended to be added to the second term of the Riera function in the case in which the impact velocity is in the range of 70 m/s to 200 m/s.

scholarly journals Dynamic characteristics of mistuned bladed disk system under rub-impact force

2020 ◽  
Vol 12 (11) ◽  
pp. 168781402097306
Author(s):  
Hui Zhang ◽  
Tianyu Zhao ◽  
Hongyuan Zhang ◽  
Honggang Pan ◽  
Huiqun Yuan
Keyword(s):  
Finite Element ◽  
Variable Thickness ◽  
Impact Force ◽  
Element Model ◽  
Force Model ◽  
Disk System ◽  
Element Analysis ◽  
Bladed Disk ◽  
Blade Tip ◽  
The Impact

In order to study the rubbing of the mistuned bladed disk system with variable thickness blades, an elastically supported shaft-variable thickness blades coupled finite element model is established in this paper. A new rubbing force model is proposed considering the variable thickness section characteristics and rotation effect of the variable thickness blade. A method of mistuned parameter identification is introduced which consists of static frequency testing of blades, dichotomy, and finite element analysis. Based on the finite element method, the mistuned bladed disk system is made dynamic analysis in full rubbing by applying the judgment load method. The dynamic response of the mistuned bladed disk system is discussed under different conditions. The results show that increasing the amount of mistuning will increase the system vibration. At high speeds, the impact force will be partially offset by centrifugal force. And the rubbing gap affects the form of rubbing. With the gap decreases, the system will change from intermittent rubbing to continuous rubbing. In addition, when the system is rubbed, due to energy dissipation and blade damping, the stress is transferred from the blade tip to the blade root and attenuated. In general, rubbing is a random complex nonlinear vibration process.

Response of Dolos Concrete Armor Units to Impact Loads

1991 ◽  
Vol 113 (4) ◽  
pp. 286-291 ◽  
Author(s):  
J. W. Tedesco ◽  
P. B. McGill ◽  
W. G. McDougal
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Material Properties ◽  
Concrete Strength ◽  
Impact Resistance ◽  
Nonlinear Material ◽  
Impact Loads ◽  
Model Formulation ◽  
Element Analysis ◽  
The Impact

A finite element analysis is conducted to determine the critical impact velocities for concrete dolos. The model formulation includes deformations at the contact surface and nonlinear material properties. Two dolos orientations are considered: vertical fluke seaward and horizontal fluke seaward. In both cases, the larger units fail at lower angular impact velocities. It is also shown that doubling the concrete strength increases the impact resistance by approximately 40 percent.

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.

Finite Element Analysis of High-Decker Bus Frontal Impact Based on ECE-Regulation No.29

2013 ◽  
Vol 658 ◽  
pp. 464-470
Author(s):  
Supakit Rooppakhun ◽  
Sarawut Bua-Ngam
Keyword(s):  
Finite Element ◽  
Impact Analysis ◽  
Three Dimensional ◽  
Fe Model ◽  
Frontal Impact ◽  
Total Deformation ◽  
United Nations Economic Commission ◽  
Element Analysis ◽  
Bus Structure ◽  
The Impact

In Thailand, according to the bus accident statistics referred to Department of Land Transport (DLT), the highest risk represents the frontal crash accidents. In case of frontal crashworthiness, the high- decker bus safety was referred to the regulation no.29 of United Nations Economic Commission for Europe (ECE-R29). In this study, the frontal impact analysis of the high-decker passenger bus structure based on ECE-R29 using Finite Element (FE) analysis was focused on. The energy absorption including to the total deformation of the frontal cabin were evaluated. Three-dimensional FE model of frontal bus structure with- and without- simple impact attenuator were created and analyzed using ANSYS/Explicit software. In accordance with the results, the average magnitude of kinetic energy in case of impact attenuator revealed the value lower than those without impact attenuator owing to absorb energy in the impact attenuator. In addition, the total deformation regarding to the safe zone of the frontal cabin in the case of with impact attenuator were lower than without impact attenuator as 75.8%. Therefore, the frontal impact attenuator should be recommended to a high-decker bus for the driver protection in the event of crash accident.

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