A New Equation of Motion to Calculate the Impact Force and the Energy Dissipation

2013 ◽  
Author(s):  
H. Naderpour ◽  
R.C. Barros ◽  
S.M. Khatami
Keyword(s):  
Energy Dissipation ◽  
Impact Force ◽  
Equation Of Motion ◽  
New Equation ◽  
The Impact

Discussions on the Principle to Reduce the Sliding Fall Rock Impact Force against Protective Structure

2011 ◽  
Vol 378-379 ◽  
pp. 23-26
Author(s):  
Wen Jie Niu
Keyword(s):  
Energy Dissipation ◽  
Impact Force ◽  
Bending Stiffness ◽  
Protective Structure ◽  
Steel Column ◽  
Protective System ◽  
The Impact ◽  
Non Destructive

Passive ductile protective system is widely used because of its better performance than buttress wall. This paper intends to determine the sliding fall rock impact force against a steel column at first. Then the rigid protective structure and ductile protective structure were compared. At last the hidden principle that passive ductile protective system can reduce the impact force was revealed. Results indicate that rings for energy dissipation in passive ductile protective system can significantly decrease the bending stiffness EI and decrease the impact force. Buttress wall encounters a lot more impact force than passive ductile protective system because of its bulkiness. Thus to ensure the buttress wall non-destructive, the thickness of buttress wall increases and it is not economic.

Application of 'UREAD' for the Energy Dissipation in Engineering Structures

2011 ◽  
Vol 486 ◽  
pp. 1-4
Author(s):  
Fayek H. Osman ◽  
Rocco Lupoi
Keyword(s):  
Energy Dissipation ◽  
Equal Channel Angular Extrusion ◽  
Impact Force ◽  
Impact Loads ◽  
Device Performance ◽  
Engineering Structures ◽  
Dynamic Impacts ◽  
Deformable Materials ◽  
The Impact ◽  
Shear Planes

A concept based upon Equal Channel Angular Extrusion (ECAE) is developed and introduced in the form of a Universal Re-usable Energy Absorption Device ‘UREAD’. In impact situations the device utilises the energy required to extrude deformable materials through the shear planes of a set of intersecting channels and hence provides the means to protect engineering structures. The impact force is absorbed through the resistance of a deformable material and the energy is dissipated through an operational stroke. This paper examines the use of this new concept under dynamic loading. The device performance and usability during dynamic impacts are tested in a landing frame type experiment where the effectiveness of the technique in reducing impact loads and energy are also examined.

The Behaviour of the Impact Damper

1965 ◽  
Vol 180 (1) ◽  
pp. 895-906 ◽  
Author(s):  
M. M. Sadek
Keyword(s):  
Differential Equation ◽  
Impact Force ◽  
Equation Of Motion ◽  
Dynamic Equations ◽  
Vibrational Amplitude ◽  
Time Curve ◽  
Impact Damper ◽  
Rectangular Shape ◽  
Force Time ◽  
The Impact

In this investigation a theory is developed relating to the behaviour of the impact damper. The analysis is based on the assumptions that (1) two un-equispaced impacts per cycle occur in the steady state, and (2) the impact force-time curve is of rectangular shape and of infinitesimal duration. Fourier series are used to represent the impact cycle and the differential equation of motion is derived. This is solved using the dynamic equations of impact to determine the boundary conditions. Three equations are developed to determine the variation of impulse, phase angle and vibrational amplitude with the change of the damper parameters. Resonance curves are obtained and the theory is examined experimentally. The regions of validity of the above assumptions are studied both theoretically and experimentally. Non-linearity in the behaviour of this damper is very clear, especially in the range of its optimum behaviour. Two design curves are developed which can be used to determine the damper parameters necessary for a certain amplitude reduction.

Some thought on the Estimating of the Impact Force by an Experiment

2019 ◽  
Vol 7 (2) ◽  
pp. 205-213
Author(s):  
Yong-Doo Kim ◽  
Seung-Jae Lim ◽  
Hyun-Ung Bae ◽  
Kyoung-Ju Kim ◽  
Chin-Ok Lee ◽  
...  
Keyword(s):  
Impact Force ◽  
The Impact

scholarly journals Assessing Habitat Vulnerability and Loss of Naturalness: Applying the GLOBIO3 Model in the Czech Republic

2021 ◽  
Vol 13 (10) ◽  
pp. 5355
Author(s):  
Vilém Pechanec ◽  
Ondřej Cudlín ◽  
Miloš Zapletal ◽  
Jan Purkyt ◽  
Lenka Štěrbová ◽  
...  
Keyword(s):  
Land Use ◽  
Czech Republic ◽  
Habitat Quality ◽  
Species Abundance ◽  
Biodiversity Loss ◽  
Infrastructure Development ◽  
Natural Habitats ◽  
The Czech Republic ◽  
New Equation ◽  
The Impact

Global and regional biodiversity loss is caused by several drivers including urban development, land use intensification, overexploitation of natural resources, environmental pollution, and climate change. The main aim of our study was to adapt the GLOBIO3 model to the conditions of the Czech Republic (CR) to assess loss of naturalness and biodiversity vulnerability at the habitat level on a detailed scale across the entire CR. An additional aim was to assess the main drivers affecting the biodiversity of habitat types. The GLOBIO3 model was adapted to CZ-GLOBIO by adapting global to local scales and using habitat quality and naturalness data instead of species occurrence data. The total mean species abundance (MSA) index of habitat quality, calculated from the spatial overlay of the four MSA indicators by our new equation, reached the value 0.62. The total value of MSA for natural and near-natural habitats was found to be affected mainly by infrastructure development and fragmentation. Simultaneously, intensity of land use change and atmospheric nitrogen deposition contributed primarily to the low total value of MSA for distant natural habitats. The CZ-GLOBIO model can be an important tool in political decision making to reduce the impact of the main drivers on habitat biodiversity in the CR.

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.

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

2017 ◽  
Vol 9 (3) ◽  
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.

Study on Impact Compaction of Aeolian Sand Subgrade and its Effect Evaluation

2011 ◽  
Vol 378-379 ◽  
pp. 370-373
Author(s):  
Yu Qing Yuan ◽  
Xuan Cang Wang ◽  
Hui Jun Shao
Keyword(s):  
Rayleigh Wave ◽  
Impact Force ◽  
Engineering Practice ◽  
Effect Evaluation ◽  
Aeolian Sand ◽  
Field Compaction ◽  
Vibratory Compaction ◽  
Strength And Stiffness ◽  
The Impact ◽  
Elastic Stage

In order to solve the problem of aeolian sand subgrade compaction, we studied the technology of impact compaction, applied it to the engineering practice and analyzed its effect with Rayleigh wave. The technology of impact compaction can combine the compaction of potential energy and kinetic energy and make it easier for the materials to reach their elastic stage. With the combined function of "knead-roll-impact", the impact compaction road roller can compact the soil body and offer 6～10 times impact force and 3～4 times the depth of influence more than the vibratory roller. The impact compaction methods of aeolian sand subgrade were put forward. The comparative field compaction tests between impact and vibratory compaction are carried through, which are detected by Rayleigh wave. The results show that the impact compaction can make the density of the aeolian sand subgrade 2～5% higher than the vibratory compaction, and reach the influence depth of 7 metres. To sum up, the impact compaction can clearly increases the strength and stiffness of aeolian sand subgrade with a dynamic elastic modulus of 202.63MPa.

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