Analysis of Vehicle Tire Impact Force Based on Collision Model

2014 ◽  
Vol 945-949 ◽  
pp. 576-580
Author(s):  
Wen Jun Ma ◽  
Xin Guan ◽  
Ping Ping Lu
Keyword(s):  
Impact Force ◽  
Model Simulation ◽  
Coefficient Of Restitution ◽  
Collision Model ◽  
Impact Function ◽  
Complex Process ◽  
Language Analysis ◽  
Hysteretic Damping ◽  
Vertical Landing ◽  
Damping Model

The effect of impact force on vehicle tires is a complex process. Accurately chassis dynamics analysis need to consider the influence of impact force. This paper uses collision model to solve it and then successfully establish Impact function model Hysteretic damping model and Modified hysteretic damping model based on the C language. Analysis the result of impact contact force of tire vertical landing. In the coefficient of restitution close to 1, the simulation results of the three models have no greater difference. While the Hysteretic damping model simulation result is different from the other two models in the coefficient of restitution is relatively small.

Analysis of Parameters Affecting Impact Force Attenuation during Landing in Human Vertical Free Fall

1982 ◽  
Vol 11 (3) ◽  
pp. 141-147 ◽  
Author(s):  
J Mizrahi ◽  
Z Susak
Keyword(s):  
Early Phase ◽  
Impact Force ◽  
Body Position ◽  
Free Fall ◽  
Muscle Action ◽  
Impact Forces ◽  
Ground Roll ◽  
Vertical Landing

The characteristics of impact forces on the legs during vertical landing of human vertical free fall in different falling conditions were studied to reveal the parameters which take part in the attenuation of these impact forces. The following parameters were investigated: body position during landing, range of flexion of the joints of the legs at impact, usage of ground-roll immediately after impact and softness of the ground. The results indicate that joint movements and muscle action play a major role in reducing peak forces during landing. This emphasizes the importance of adequate training to improve the pre-programmed non-reflex muscle action, necessary in the early phase of impact.

scholarly journals Reflections on the Hysteretic Damping Model

2009 ◽  
Vol 16 (5) ◽  
pp. 529-542 ◽  
Author(s):  
Nuno Maia
Keyword(s):  
Free Vibration ◽  
Point Of View ◽  
The Other ◽  
Hysteretic Damping ◽  
Engineering Problems ◽  
Practical Engineering ◽  
The Subject ◽  
The One ◽  
Damping Model ◽  
Free Vibration Response

This paper presents a reflection on a recently proposed solution to the problem of the free vibration response with the constant hysteretic damping model, that has been presented in some conferences in recent years, by the author himself and some of his colleagues. On the one hand, as expected, the subject has been received with natural criticism, mainly due to the well-known non-causal behaviour of the model in free vibration. On the other hand, it was not easy to understand what could be wrong in that proposal, as apparently everything was perfect from a mathematical point of view. The author decided that this subject deserved a more careful and detailed analysis and – in this kind of tutorial paper – the issue seems to have been clarified. It is concluded that the proposed solution involving the constant hysteretic damping corresponds in fact to an equivalent viscously damped model; it is therefore concluded that the application of the constant hysteretic damping to model the free vibration of practical engineering problems should be considered only in the perspective of an equivalent viscously damped model.

Analysis of Influence of Material Damping on the Dynamic Response of Concrete-Filled Square Steel Tubular Columns

2012 ◽  
Vol 226-228 ◽  
pp. 905-909
Author(s):  
Yuan Feng Wang ◽  
Xiao Ran Li
Keyword(s):  
Dynamic Response ◽  
Loss Factor ◽  
Stress Amplitude ◽  
Dynamic Equilibrium ◽  
Dynamic Responses ◽  
Tubular Columns ◽  
Hysteretic Damping ◽  
Cfst Columns ◽  
Stress Dependent ◽  
Damping Model

The damping characteristic and dynamic responses of the concrete-filled square steel tubular (CFST) columns were numerically investigated in this paper. Finite element iteration method in the hysteretic damping system for CFST materials was presented, and an improved method considering viscous damping dynamic equilibrium equation with hysteretic damping model was also proposed. Based on the proposed methods, the loss factor and dynamic response of CFST columns subjected to the earthquake and harmonic loadings were effectively calculated. The results indicate that the stress-dependent damping method induces a larger dynamic response, and the loss factor of the CFST columns increases with the increase of the stress amplitude and lower steel ratio.

Experimental Evaluation of a Metal Mesh Bearing Damper in Parallel With a Structural Support

2001 ◽  
Author(s):  
Eyad M. Al-Khateeb ◽  
John M. Vance
Keyword(s):  
Stainless Steel ◽  
Wire Mesh ◽  
Squeeze Film ◽  
Hysteretic Model ◽  
Metal Mesh ◽  
Critical Speeds ◽  
Squirrel Cage ◽  
Hysteretic Damping ◽  
Damping Model ◽  
Copper Mesh

In a previous ASME paper experiments were reported on metal mesh bearing dampers (MMD) that were tested in a power turbine rotor at speeds up to 12,000 rpm. They were made of 0.229 mm stainless steel 304 wire mesh, compressed to 57% density, which is close to the maximum density that was economically available. After balancing, a level of vibration was achieved similar to that previously observed with squeeze film dampers. These experiments showed that the MMD could suppress vibration amplitudes of the 22.7 kg rotor at critical speeds of 4,000 rpm and 9,300 rpm. Much of the testing showed the rotor having little or no response to unbalance on coastdown through the critical speeds. The donut-shaped MMD in those tests were the only bearing supports; no squirrel cages were used. A question was raised about the feasibility of using MMD in parallel with a squirrel cage bearing support so that the stiffness can be controlled independently of the damping. This paper presents experimental results for metal mesh dampers with a squirrel cage as a parallel bearing support. Experiments with copper mesh as seal elements (on another project) had indicated that copper mesh has higher damping than stainless steel, so copper was chosen for these experiments. Both a linear viscous damping model and a hysteretic damping model were investigated. Some hysteretic damping models predict that damping depends on stiffness. A different hysteretic model turned out to be useful and promising as a prediction model for two reasons: a) it fits the measured data, and b) it predicts that the damping is not lost if the MMD is put in parallel with a steel structure such as a squirrel cage bearing support. The measurements reported here support the validity of that prediction.

The Efficacy of Impact-Absorbing Materials during Collision with a Soccer Ball

2013 ◽  
Vol 440 ◽  
pp. 363-368
Author(s):  
Zahari Taha ◽  
Mohd Hasnun Arif Hassan ◽  
Mohd Azri Aris
Keyword(s):  
High Speed ◽  
Impact Force ◽  
Coefficient Of Restitution ◽  
Soccer Ball ◽  
Absorbing Materials ◽  
The Subject ◽  
The Impact ◽  
The Brain ◽  
Peak Impact Force ◽  
Impact Duration

The uniqueness of soccer is that the players are allowed to use their head to pass the ball to a teammate of even try to score goal. Studies have shown that heading in soccer might be dangerous to the brain and could lead to brain trauma. There are headgears available for soccer players to protect their head, but studies have proven that currently available headgears are ineffective in reducing the impact caused by a soccer ball. The objective of this study is to test the efficacy of six different types of impact-absorbing materials in reducing the linear impact force from a soccer ball. The soccer ball was dropped from the height of 2.3 m onto a force platform to measure the impact force. A high-speed camera is used to record the motion and the impact duration, and then the coefficient of restitution for each impact was determined. Polyurethane (PU) comb-gel was found to be the most effective material in reducing the peak impact force and impulse compared with other materials. The reduction in peak force was associated with longer impact duration between the soccer ball and the PU comb-gel. However, the coefficient of restitution was reduced by 21.7%, implying that using the gel alone will reduce the speed of the ball after heading, thus reducing the performance of a player wearing it. A combination of PU gel and another stiffer material is suggested and the effectiveness of the composite will be the subject of future investigation.

scholarly journals Model Simulation of Soybean (Glycine Max (L.) Merrill) Growth by Energy Balance Approach

Agromet ◽  
2018 ◽  
Vol 32 (1) ◽  
pp. 31
Author(s):  
Fajar Syofwan ◽  
Handoko Handoko
Keyword(s):  
Energy Balance ◽  
Dry Matter ◽  
Model Simulation ◽  
Biomass Growth ◽  
Complex Process ◽  
Glycine Max L ◽  
Intercepted Solar Radiation ◽  
Intercepted Radiation ◽  
Energy Balance Approach ◽  
Good Agreement

<p>Intercepted solar radiation by leaf will influence energy balance in plant. The energy balance in leaf is a complex process, which results in biomass growth. Here, we modeled leaf energy balance to estimate dry matter growth in soybean. In the field, we measured intercepted radiation in canopy (1 meter above surface) with two treatments: soybean with 50% shading (N50%M0) and no-shading (N0%M0) twice a week. Then we sampled a biomass with destructive technique every week in each treatment. Our results showed that the intercepted radiation in no-shading treatment was higher (400 J/m<sup>2</sup>) than those in shading one (250 J/m<sup>2</sup>). The results were consistence with the high biomass growth at 12 weeks after planting, which observed in no-shading treatment. Then we validated our model by 1:1 plot test. Our finding revealed that no-shading treatment showed a good agreement with the observed biomass (closed to 1:1 plot), whereas the shading treatment tended to predict under estimate of biomass.</p>

Sequential and Near-Simultaneous Multi-Body Collisions

2004 ◽  
Author(s):  
D. Dane Quinn ◽  
Kalyan Bairavarasu
Keyword(s):  
Initial Conditions ◽  
Coefficient Of Restitution ◽  
Initial Configuration ◽  
Collision Model ◽  
Sufficient Distance ◽  
Initial Spacing ◽  
Compliance Model ◽  
The Masses ◽  
Multi Body ◽  
Impact Duration

This work considers a three mass collision model with finite-time, compliant contacts. If the masses are initially separated by a sufficient distance, the collision sequence is sequential, that is, comprised of a sequence of pairwise impacts. The final velocities of each mass are then independent of the specific initial spacing. In contrast, if the initial spacing between the masses is sufficiently small there exists an interval during which the three masses interact simultaneously. In this instance the final velocity state also depends on the initial configuration of the system. Given an assumed impact duration and coefficient of restitution for a pairwise collision, a two-dimensional map is derived to describe those initial conditions that lead to pairwise sequences. Finally, for a specific nonlinear compliance model the variation in the final velocities is characterized in terms of the initial configuration and velocity state of the system.

Effect of the elastic hysteresis term formulation and response to non-harmonic periodic excitations of a non-linear SDOF dynamical model with weak frequency-dependency in the time domain

2021 ◽  
pp. 095440622110182
Author(s):  
Christos Spitas ◽  
Mahmoud S Dwaikat ◽  
Vasileios Spitas
Keyword(s):  
Correction Factor ◽  
Time Domain ◽  
Hysteresis Loops ◽  
Domain Model ◽  
Viscous Damping ◽  
State Variables ◽  
Hysteretic Damping ◽  
Vibration Responses ◽  
The Time Domain ◽  
Damping Model

We elaborate a SDOF time-domain model for elastic hysteretic damping, by modifying the viscous damping model to introduce an instantaneous correction factor that recursively depends on the state variables of the system, such that the response exhibits weak dependency on frequency, corresponding to a large array of engineering materials. The effect of different formulations for calculating the instantaneous correction factor on the predicted hysteresis loops and the potential manifestation of singularities is studied. Hysteresis loops anticipated by the model are plotted and forced vibration responses to harmonic and other periodic non-harmonic excitations are simulated and discussed, also in comparison to the conventional viscous and Reid’s damping models.

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