A Method for Determining Impact Force for Single and Tri Axis Resonant Plate Shock Simulations

In sport climbing, a common method of belaying is to use a static rope brake attached to the belayer’s harness, but the belayer can move freely. This paper investigates the dynamics of a climbing fall with such a belayer. The dynamics are nontrivial because of the belayer’s constraint to be always at or above his initial position. An exact solution for a linear elastic rope is presented. Compared to a fix-point belay, one obtains a considerable force reduction on the belay-chain. However, there is a trade-off of a longer stopping distance of both climber and belayer. In order to calculate the stopping distance, friction between rope and the top carabiner has been taken into account. Closed-form formulas allow for calculating the maximum impact force, as well as the minimum mass of the belayer which is necessary to hold a fall from a certain height.

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On the impact force analysis of two-leg landing with a flexed knee

Computer Methods in Biomechanics & Biomedical Engineering ◽

10.1080/10255842.2021.1925257 ◽

2021 ◽

pp. 1-14

Author(s):

Marzieh Mojaddarasil ◽

Mohammad Jafar Sadigh

Keyword(s):

Impact Force ◽

Force Analysis ◽

The Impact

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Impact force reconstruction and localization using nonconvex overlapping group sparsity

Mechanical Systems and Signal Processing ◽

10.1016/j.ymssp.2021.107983 ◽

2022 ◽

Vol 162 ◽

pp. 107983

Author(s):

Junjiang Liu ◽

Baijie Qiao ◽

Yuanchang Chen ◽

Yuda Zhu ◽

Weifeng He ◽

...

Keyword(s):

Impact Force ◽

Group Sparsity ◽

Overlapping Group Sparsity ◽

Force Reconstruction

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

REVIEWS ON ADVANCED MATERIALS SCIENCE ◽

10.1515/rams-2021-0020 ◽

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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Investigate Impact Force of Dam-Break Flow against Structures by Both 2D and 3D Numerical Simulations

Water ◽

10.3390/w13030344 ◽

2021 ◽

Vol 13 (3) ◽

pp. 344

Author(s):

Le Thi Thu Hien ◽

Nguyen Van Chien

Keyword(s):

Impact Force ◽

Numerical Models ◽

Splitting Method ◽

Dam Break ◽

Navier Stokes ◽

Dynamic Force ◽

Exact Mass ◽

Initial Water ◽

Dam Break Flow ◽

2D And 3D

The aim of this paper was to investigate the ability of some 2D and 3D numerical models to simulate flood waves in the presence of an isolated building or building array in an inundated area. Firstly, the proposed 2D numerical model was based on the finite-volume method (FVM) to solve 2D shallow-water equations (2D-SWEs) on structured mesh. The flux-difference splitting method (FDS) was utilized to obtain an exact mass balance while the Roe scheme was invoked to approximate Riemann problems. Secondly, the 3D commercially available CFD software package was selected, which contained a Flow 3D model with two turbulent models: Reynolds-averaged Navier-Stokes (RANs) with a renormalized group (RNG) and a large-eddy simulation (LES). The numerical results of an impact force on an obstruction due to a dam-break flow showed that a 3D solution was much better than a 2D one. By comparing the 3D numerical force results of an impact force acting on building arrays with the existence experimental data, the influence of velocity-induced force on a dynamic force was quantified by a function of the Froude number and the water depth of the incident wave. Furthermore, we investigated the effect of the initial water stage and dam-break width on the 3D-computed results of the peak value of force intensity.

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Dry granular avalanche impact force on a rigid wall of semi-infinite height

EPJ Web of Conferences ◽

10.1051/epjconf/201714003054 ◽

2017 ◽

Vol 140 ◽

pp. 03054 ◽

Cited By ~ 3

Author(s):

Adel Albaba ◽

Stéphane Lambert ◽

Thierry Faug

Keyword(s):

Impact Force ◽

Rigid Wall ◽

Infinite Height ◽

Granular Avalanche

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The Study on Crashworthiness Performance of Thin-Walled Structures and the Effect of Welding Performance on it

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.63-64.655 ◽

2011 ◽

Vol 63-64 ◽

pp. 655-658

Author(s):

Qi Hao ◽

Sheng Jun Wu

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Welded Joints ◽

Impact Force ◽

Deformation Energy ◽

Optimal Shape ◽

Explicit Finite Element Method ◽

Explicit Finite Element ◽

Thin Walled Structures ◽

Thin Walled

Explicit finite element method is adopted to simulate the crashworthiness performance of four types of typical thin—walled structures used in vehicle by software LS-DYNA. The structures with the same material、area and length are crash by a rigid body with 40km/h in10ms, The crash processes and crashworthiness characters are analyzed by a series crash parameters: deformation energy with unit displacement, impact force and deceleration to look for the optimal shape with crashworthiness. With comparing, the double caps section has ascendant performance than the others. The simulating methods of welded-joints are discussed to analysis their effects on crashworthiness simulation.

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Pre-Impact Configuration Designing of a Robot Manipulator for Impact Minimization

Journal of Mechanisms and Robotics ◽

10.1115/1.4035373 ◽

2017 ◽

Vol 9 (3) ◽

Cited By ~ 2

Author(s):

Jingchen Hu ◽

Tianshu Wang

Keyword(s):

Impact Force ◽

Robot Manipulator ◽

Analytical Formula ◽

Joint Space ◽

Collision Problem ◽

Spatial Operator ◽

Inertia Ellipsoid ◽

The Impact ◽

Maximum Minimum ◽

Simple Analytical Formula

This paper studies the collision problem of a robot manipulator and presents a method to minimize the impact force by pre-impact configuration designing. First, a general dynamic model of a robot manipulator capturing a target is established by spatial operator algebra (SOA) and a simple analytical formula of the impact force is obtained. Compared with former models proposed in literatures, this model has simpler form, wider range of applications, O(n) computation complexity, and the system Jacobian matrix can be provided as a production of the configuration matrix and the joint matrix. Second, this work utilizes the impulse ellipsoid to analyze the influence of the pre-impact configuration and the impact direction on the impact force. To illustrate the inertia message of each body in the joint space, a new concept of inertia quasi-ellipsoid (IQE) is introduced. We find that the impulse ellipsoid is constituted of the inertia ellipsoids of the robot manipulator and the target, while each inertia ellipsoid is composed of a series of inertia quasi-ellipsoids. When all inertia quasi-ellipsoids exhibit maximum (minimum) coupling, the impulse ellipsoid should be the flattest (roundest). Finally, this paper provides the analytical expression of the impulse ellipsoid, and the eigenvalues and eigenvectors are used as measurements to illustrate the size and direction of the impulse ellipsoid. With this measurement, the desired pre-impact configuration and the impact direction with minimum impact force can be easily solved. The validity and efficiency of this method are verified by a PUMA robot and a spatial robot.

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