A Novel Stabilized Integration in Meshfree Modeling for the Impact Problems

2021 ◽  
Author(s):  
Sheng-Wei Chi ◽  
Mohammed Mujtaba Atif
Keyword(s):  
Impact Problems ◽  
The Impact

Resolving the Unique Invariant Slip-Direction in Rigid Three-Dimensional Multi-Point Impacts at Stick-Slip Transitions

2018 ◽  
Author(s):  
Abhishek Chatterjee ◽  
Alan Bowling
Keyword(s):  
Single Point ◽  
Three Dimensional ◽  
Impact Behavior ◽  
Slip Direction ◽  
Stick Slip ◽  
Impact Forces ◽  
Post Impact ◽  
Impact Problems ◽  
Slip Transition ◽  
The Impact

This work presents a new approach for resolving the unique invariant slip direction at Stick-Slip Transition during impact. The solution method presented in this work is applicable to both single-point and multi-point impact problems. The proposed method utilizes rigid body constraints to resolve the impact forces at all collision points in terms of a single independent impact forces parameter. This work also uses an energetic coefficient of restitution to terminate impact events, thereby yielding energetically consistent post-impact behavior.

scholarly journals A REVIEW ON THE IMPACT OF THE COVID-19 PANDEMIC ON THE HEALTH CARE SECTOR

2021 ◽  
pp. 1-6
Author(s):  
PRAJITHA BIJU ◽  
PALLAVI K. ◽  
VAGEESH REVADIGAR ◽  
SONAL DSOUZA ◽  
MOHAMMED ASIF IQBAL ◽  
...  
Keyword(s):  
Health Care ◽  
Initial Period ◽  
Health Care Sector ◽  
Healthcare Sector ◽  
Future Challenges ◽  
Artificial Intelligence Technology ◽  
Pharmaceutical Industries ◽  
Impact Problems ◽  
The One ◽  
The Impact

The global crisis of the present era, the COVID-19 pandemic, has changed given new normal ways in many of the sectors. The present review highlights the impact, problems, and challenges faced by major areas of the health care sector due to pandemics and also addresses some of the aspects of upcoming approaches. The healthcare sector is the one sector that is on-demand since this COVID-19 pandemic raised. During the initial period, there was disruption of various services provided by the health care sector due to supply chain management issues and reduction in demand by consumers, quarantine, and lockdown period. The healthcare workers also confronted a huge challenge due to the increased number of cases and shortage of amenities and safety measures. This significantly affected even COVID-19 patients and the general public suffering from other diseases. To fight this issue, research and development (RandD) in pharmaceutical industries with great efforts to explore molecules and save many lives. Gradually innovative ways to strengthen and combat pandemics started emerging. Numeral ways and rules were adopted to prevent, diagnose and cure the disease. Artificial intelligence technology has emerged as one of the boons to address many of the unresolved or time-consuming mysteries. All the divisions of health care sectors have started working more efficiently with adopted new strategies to face future challenges.

Fracture in Taylor Rod Impact Test Specimens

2010 ◽  
Author(s):  
Sachin S. Gautam ◽  
Ravindra K. Saxena ◽  
P. M. Dixit
Keyword(s):  
Ductile Fracture ◽  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Outer Edge ◽  
Impact Surface ◽  
Mechanics Model ◽  
Contact Impact ◽  
Impact Problems ◽  
The Impact ◽  
Aisi1045 Steel

High velocity contact-impact problems are of great interest in industries related to aerospace, mechanical and civil engineering. Ductile fracture often occurs in such applications. Taylor rod impact tests are used as experimental and numerical tests for determining the mechanical behaviour of materials subjected to high strain rates. At sufficiently high velocities, a significant plastic deformation leading to fracture is observed. In this paper, ductile fracture in Taylor rod made of AISI1045 steel is simulated using a continuum damage mechanics model. Simulations are performed for the velocity of 250 and 300 m/s. It is observed that, at lower velocities, tensile cracks are observed at the outer edge of the impact surface. On the other hand, at higher velocities, the fracture is observed at the central axis (confined fracture) as well as at the outer edge leading to fragmentation. Both the results are consistent with the experimental results available in the literature.

Mechanical Aspects of the Dynamic Tear Test

1969 ◽  
Vol 91 (3) ◽  
pp. 535-543 ◽  
Author(s):  
G. E. Nash ◽  
E. A. Lange
Keyword(s):  
Crack Initiation ◽  
Bending Moments ◽  
Simple Analysis ◽  
Transverse Beam ◽  
Fracture Characteristics ◽  
Impact Forces ◽  
Impact Problems ◽  
The Impact

The impact forces and specimen bending moments generated during the NRL dynamic tear test are interpreted in terms of the dynamics of the system and the fracture characteristics of the material. It is shown that the impact forces and bending moments up to the time of crack initiation can be predicted using a simple analysis based on Timoshenko’s treatment of transverse beam impact problems. This implies the possibility of using this analysis for dynamic KIc determinations.

scholarly journals Impact of a rigid body against a half-infinite elastic bar

1988 ◽  
Vol 10 (1) ◽  
pp. 28-33
Author(s):  
Nguyen Dang To
Keyword(s):  
Rigid Body ◽  
Longitudinal Vibration ◽  
Vibration Theory ◽  
Elastic Bar ◽  
Impact Problems ◽  
The Impact ◽  
Precise Theory ◽  
Impact Problem

The solution of the impact - problems of a rigid body against an elastic bar arc before based on the classical longitudinal vibration theory of elastic bar. In this paper, we are using a more precise theory to deal with the impact problem of a rigid body against a half -infinite elastic bar with an elastic gasket. This problem is solved completely.

Influence of added mass on ice impacts

1988 ◽  
Vol 15 (4) ◽  
pp. 698-708 ◽  
Author(s):  
Michael Isaacson ◽  
Kwok Fai Cheung
Keyword(s):  
Contact Point ◽  
Added Mass ◽  
Offshore Structures ◽  
Impact Model ◽  
Ocean Engineering ◽  
Offshore Structure ◽  
Proposed Model ◽  
Impact Problems ◽  
Ice Impacts ◽  
The Impact

The present paper applies potential theory to describe the variation of the added mass of an iceberg and its coupling effects on an offshore structure for various separation distances up to the point of contact. The strengths and weaknesses of the proposed model are discussed together with its practical application in ice mass impact problems. An impact model based on dynamic analysis is developed to calculate the impact force and response of a structure for head-on collisions. Both the contact-point added mass estimated in the present study and the traditionally assumed far-field added mass are used in the impact model separately. The results are compared and the crucial roles played by the ambient fluid during impact are discussed. Key words: added mass, hydrodynamics, ice impact, ocean engineering, offshore structures.

A nonlinear strain rate and pressure-dependent micro-mechanical composite material model for impact problems

2017 ◽  
Vol 31 (12) ◽  
pp. 1634-1660 ◽  
Author(s):  
Sandeep Medikonda ◽  
Ala Tabiei
Keyword(s):  
Composite Material ◽  
Strain Rate ◽  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Material Model ◽  
Distribution Functions ◽  
Failure Behavior ◽  
Nonlinear Strain ◽  
Impact Problems ◽  
The Impact

A micro-mechanical composite material model is developed to simulate the behavior of unidirectional composites under impact loading conditions in the nonlinear finite element solver (LS-DYNA®). The nonlinear strain rate and pressure dependency in the composite material model is accounted by the resin, which uses previously developed state variable viscoplastic equations. These equations have been originally developed for metals; however, these are modified to account for the significant contributions of hydrostatic stresses typically observed in polymers. The material model also uses a continuum damage mechanics (CDM) based failure model to incorporate the progressive post-failure behavior. A set of Weibull distribution functions are used to quantify this behavior, and a methodology of assigning physical significance to the choice of damage/softening parameters used in these functions is presented. The impact response of composite laminate plates has been simulated and compared to the experiments. It has been observed that the predicted results compare favorably to the experiments.

scholarly journals On the solution of asymptotic impact problems with significant localised indentation

2016 ◽  
Vol 231 (5) ◽  
pp. 807-822 ◽  
Author(s):  
Akuro Big-Alabo ◽  
Matthew P Cartmell ◽  
Philip Harrison
Keyword(s):  
Numerical Solutions ◽  
Nonlinear Models ◽  
Infinite Plate ◽  
Nonlinear Odes ◽  
Wide Range ◽  
Contact Models ◽  
Scope Of Application ◽  
Impact Problems ◽  
The Impact ◽  
Impact Events

A major challenge in studying impact problems analytically is solving the governing equations of impact events, which are mostly in the form of nonlinear ODEs. This paper focuses on the solution of nonlinear models for impact problems in asymptotic cases, where local indentation is significant. The asymptotic cases consist of both half-space and infinite plate impacts, which cover a wide range of practical impact events. A so-called force–indentation linearisation method (FILM), first described in a previous study, is reformulated here in a more general form in order to broaden its scope of application. The generalisation of the FILM facilitates stable and convergent solutions even when complex nonlinear contact models are used to estimate the impact force. Simulations based on the FILM approach are validated using numerical solutions.

Variational Method for Percussion Motion of a Non-Ideal Constraint System

2010 ◽  
Vol 145 ◽  
pp. 5-9
Author(s):  
Wen Li Yao ◽  
Lu Lu Gao
Keyword(s):  
Variational Method ◽  
Constraint Forces ◽  
Constraint System ◽  
System A ◽  
Practical Engineering ◽  
Ideal Constraint ◽  
Impact Problems ◽  
Method Of Lagrange Multipliers ◽  
The Impact ◽  
Impact Motion

The purpose is to study the variational method for impact problem of a non-ideal constraint system. Compared to an ideal constraint system, a non-ideal constraint system has more practical engineering background, but it contains unknown non-ideal constraint forces, which usually can be written as the function of ideal constrained forces. The existing analytical method on ideal constraint systems does not contain constraint forces. The non-ideal constraint forces are considered for impact problems in the variational principle, and then by method of Lagrange multipliers, equations for impact motion of a holonomic system and an expression of the kinetic energy variation during the impact motion are obtained.

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