Impulse Correlation Ratio in Solving Multiple Impact Problems

2000 ◽  
pp. 235-273 ◽  
Author(s):  
Yildirim Hurmuzlu ◽  
Viorel Ceanga
Keyword(s):  
Correlation Ratio ◽  
Impact Problems ◽  
Multiple Impact

Solving frictionless rocking block problem with multiple impacts

2009 ◽  
Vol 465 (2111) ◽  
pp. 3323-3339 ◽  
Author(s):  
Cuneyt Yilmaz ◽  
Mohamed Gharib ◽  
Yildirim Hurmuzlu
Keyword(s):  
Experimental Study ◽  
Coefficient Of Restitution ◽  
Correlation Ratio ◽  
Multiple Impacts ◽  
Rocking Block ◽  
Impact Problems ◽  
Multiple Impact

In this paper, we present a solution to the frictionless multiple impact problems that may arise in the rocking blocks. We use an approach based on the impulse–momentum methods, the energetic coefficient of restitution and the impulse correlation ratio. Subsequently, we present the results of an experimental study that is used to compare the results predicted by the proposed method with the experimental outcomes.

On the adaptation of local impact laws for multiple impact problems

2020 ◽  
Vol 102 (4) ◽  
pp. 1997-2016
Author(s):  
Alejandro Cosimo ◽  
Federico J. Cavalieri ◽  
Alberto Cardona ◽  
Olivier Brüls
Keyword(s):  
Local Impact ◽  
Impact Problems ◽  
Multiple Impact

scholarly journals Modelling multiple-simultaneous impact problems with a nonlinear smooth approach: pool/billiard application

2021 ◽  
Author(s):  
Raúl Gismeros Moreno ◽  
Eduardo Corral Abad ◽  
Jesús Meneses Alonso ◽  
María Jesús Gómez García ◽  
Cristina Castejón Sisamón
Keyword(s):  
Computational Cost ◽  
Nonlinear Behaviour ◽  
Friction Forces ◽  
Distinctive Features ◽  
Simultaneous Impact ◽  
Smooth Contact ◽  
Impact Problems ◽  
Multiple Impact ◽  
Impact Events

AbstractSmooth approaches are able to model reasonably well contact/impact events between two bodies, showing some peculiarities when dealing with certain geometries and arising certain issues with the detection of the initial instant of contact. The characterization of multiple-simultaneous interaction systems, considering (or not) energy dissipation phenomena (mainly friction), is always an interesting research topic, addressed from different perspectives. In the present work, the process of design, optimization and verification of a multiple-impact, day-to-day multibody novel model is shown. Specifically, we have decided to focus on a pool/billiard game due to its geometry simplicity. The model involves several balls moving freely and rolling, suffering different kinds of contacts/impacts among them and against the cushions and the cloth. In this system, the proper modelling of both contact and friction forces in the multiple, simultaneous contacts and impacts events is critical to obtain consistent results. In addition, these forces are complicated to model because of its nonlinear behaviour. The different existing approaches when dealing with multiple-contact events are briefly described, along with their most distinctive features. Then, the interactions identified on the model are implemented using several nonlinear contact-force models, following a smooth-based approach and considering friction phenomena, aiming at determining the most suitable set of both contact and friction force models for each of these implemented interactions, which take place simultaneously, thus resulting in a complex system with multiple impacts. Subsequently, the solving method that provides the most accurate results at the minimum computational cost is determined by testing a simple shot. Finally, the different interactions on the model are verified using experimental results and previous works. One of the main goals of this work is to show the some of the issues that arise when dealing with multiple-simultaneous impact multibody systems from a smooth-contact approach, and how researchers can deal with them.

Multiple Impact Based Energy Absorption

2009 ◽  
Author(s):  
Mohamed Gharib ◽  
Ahmet Celik ◽  
Yildirim Hurmuzlu
Keyword(s):  
Energy Absorption ◽  
Material Properties ◽  
Linear Chain ◽  
Contact Theory ◽  
Correlation Ratio ◽  
Hertz Contact ◽  
Post Impact ◽  
Multiple Impact ◽  
Similar Solutions ◽  
Impact Problem

In this paper, we numerically solve the elastic multiple impact problem in a linear chain of balls using the impulse-momentum and the Hertz contact theory based methods. The first method depends on a parameter called the impulse correlation ratio (ICR), while the latter one depends on the material properties and geometries of the colliding bodies. We compared the post impact velocities from the two methods and we found that the two methods yield similar solutions for elastic collisions. Then, we develop an energy absorption scheme using an arrangement of balls with different sizes. The impulse momentum method is used with the aid of the Hertz method to obtain the ICRs. We use numerical analysis to demonstrate that one can significantly improve the energy absorption by placing small balls in specific locations in a linear chain of particles.

INTENSIFICATION OF GRINDING PROCESS IN MILLS OF MULTIPLE IMPACT ACTION

2017 ◽  
Vol 11 (24) ◽  
pp. 154-161
Author(s):  
V.R. Vinokurov ◽  
◽  
E.S. Lvov ◽  
Keyword(s):  
Grinding Process ◽  
Impact Action ◽  
Multiple Impact

A three-dimensional immersed boundary method based on an algebraic forcing-point-searching scheme for water impact problems

2021 ◽  
Vol 233 ◽  
pp. 109189
Author(s):  
Bin Yan ◽  
Wei Bai ◽  
Sheng-Chao Jiang ◽  
Peiwen Cong ◽  
Dezhi Ning ◽  
...  
Keyword(s):  
Immersed Boundary Method ◽  
Three Dimensional ◽  
Immersed Boundary ◽  
Water Impact ◽  
Boundary Method ◽  
Impact Problems

scholarly journals Computer Vision-Based Bridge Damage Detection Using Deep Convolutional Networks with Expectation Maximum Attention Module

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 824
Author(s):  
Wenting Qiao ◽  
Biao Ma ◽  
Qiangwei Liu ◽  
Xiaoguang Wu ◽  
Gang Li
Keyword(s):  
Damage Detection ◽  
Complex Structure ◽  
Surface Damage ◽  
Break Point ◽  
Convolutional Networks ◽  
Concrete Crack ◽  
Current State ◽  
Bridge Damage ◽  
Bridge Inspections ◽  
Impact Problems

Cracks and exposed steel bars are the main factors that affect the service life of bridges. It is necessary to detect the surface damage during regular bridge inspections. Due to the complex structure of bridges, automatically detecting bridge damage is a challenging task. In the field of crack classification and segmentation, convolutional neural networks have offer advantages, but ordinary networks cannot completely solve the environmental impact problems in reality. To further overcome these problems, in this paper a new algorithm to detect surface damage called EMA-DenseNet is proposed. The main contribution of this article is to redesign the structure of the densely connected convolutional networks (DenseNet) and add the expected maximum attention (EMA) module after the last pooling layer. The EMA module is obviously helpful to the bridge damage feature extraction. Besides, we use a new loss function which considers the connectivity of pixels, it has been proved to be effective in reducing the break point of fracture prediction and improving the accuracy. To train and test the model, we captured many images from multiple bridges located in Zhejiang (China), and then built a dataset of bridge damage images. First, experiments were carried out on an open concrete crack dataset. The mean pixel accuracy (MPA), mean intersection over union (MIoU), precision and frames per second (FPS) of the EMA-DenseNet are 87.42%, 92.59%, 81.97% and 25.4, respectively. Then we also conducted experiments on a more challenging bridge damage dataset, the MIoU, where MPA, precision and FPS were 79.87%, 86.35%, 74.70% and 14.6, respectively. Compared with the current state-of-the-art algorithms, the proposed algorithm is more accurate and robust in bridge damage detection.

On multiple impact

1995 ◽  
Vol 59 (6) ◽  
pp. 887-902 ◽  
Author(s):  
A.P Ivanov
Keyword(s):  
Multiple Impact
Sign in / Sign up

Export Citation Format

Share Document