Three-Dimensional Modeling and Simulation of a Falling Electronic Device

2006 ◽  
Vol 2 (1) ◽  
pp. 22-31 ◽  
Author(s):  
Hua Shan ◽  
Jianzhong Su ◽  
Jiansen Zhu ◽  
Leon Xu
Keyword(s):  
Rigid Body ◽  
Electronic Device ◽  
Impact Load ◽  
Three Dimensional ◽  
The Body ◽  
Contact Dynamics ◽  
Model Verification ◽  
Multiple Impacts ◽  
Element Analysis ◽  
The Impact

This article focuses on a realistic mathematical model for multiple impacts of a rigid body to a viscoelastic ground and its comparison to theoretic results. The methodology is used to study impact on an electronic device. When an electronic device drops to the floor at an uneven level, the rapid successions of impact sequence are important for their shock response to internal structure of the devices. A three-dimensional, continuous contact, computational impact model has been developed to simulate a sequence of multiple impacts of a falling rigid body with the ground. The model simulates the impact procedure explicitly and thus is capable of providing detailed information regarding impact load, impact contact surface, and the status of the body during the impact. For the purposes of model verification, we demonstrate the numerical simulation of a falling rod problem, in which the numerical results are in good agreement with the analytic solutions based on discrete contact dynamics impact models. It is indicated by the numerical experiments that simultaneous impacts occurred to multiple locations of the body and that subsequent impacts might be larger than initial ones due to different angles of impact. The differential equation-based computational model is shown to be realistic and efficient in simulating impact sequence and laid a foundation for detailed finite element analysis of the interior impact response of an electronic device.

scholarly journals Update on Ongoing Tank Car Crashworthiness Research: Predicted Performance and Fabrication Approach

2008 ◽  
Author(s):  
Michael Carolan ◽  
David Tyrell ◽  
Brandon Talamini
Keyword(s):  
Structural Integrity ◽  
Impact Load ◽  
The Body ◽  
Rigid Punch ◽  
Load Path ◽  
Element Analysis ◽  
Structural Foam ◽  
Improved Design ◽  
Energy Absorbing ◽  
The Impact

Research is currently underway to develop strategies for maintaining the structural integrity of railroad tank cars carrying hazardous materials during collisions. This research, sponsored by the Federal Railroad Administration (FRA), has focused on four design functions to accomplish this goal: blunting the impact load, absorbing the collision energy, strengthening the commodity tank, and controlling the load path into the tank. Previous papers have been presented outlining the weight and space restrictions for this new design, as well as the approach being taken in developing the design. The performance goals for the new car have also been outlined. A key goal for the new design is the ability to contain its lading at four times the impact energy of the baseline equipment. Presently, a preliminary design has been developed that will incorporate these four functions together. This new design features a conventional commodity tank with external reinforcements to strengthen the tank. The reinforced tank is situated on a structural foam cradle, within an external carbody. This carbody has been designed utilizing welded steel sandwich panels. The body is designed to take all of the inservice loads, removing the commodity tank from the load path during normal operations. Additionally, the carbody panels will serve as an energy-absorbing mechanism in the event of a collision. Preliminary steps for fabricating and assembling the new tank car design have been outlined. These steps were developed with the intention of paralleling existing tank car fabrication process as much as is practical. Using the commercial finite element analysis (FEA) software ABAQUS/Explicit, the improved design has been analyzed for its response to an impact by a rigid punch. Simulations of two generalized impact scenarios have been made for this rigid punch impacting the improved tank car head as well as the improved tank car shell. Results of these analyses, including the force-displacement curves for both impacts, are presented within this paper. These results show that an improved-design tank car can contain the commodity for a head impact with eight times the energy of the baseline car, and four times the energy for a shell impact.

Nonlinear FEA Simulation of Thorax Considering Transient CPR and Lateral Forces

2012 ◽  
Author(s):  
Omar Awad ◽  
Yahia M. Al-Smadi
Keyword(s):  
Impact Load ◽  
Three Dimensional ◽  
Element Model ◽  
Lateral Force ◽  
The Body ◽  
Biomechanical Analysis ◽  
Lateral Impact ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
The Impact

Boxing or martial arts are games where players chests are subject to lateral impact, the impact loads travel through skin, ribs, mediastinum (i.e. a thoracic compartment) and then through the skeleton to the rest of the body. When thorax is subject to lateral force exceeding the elastic limit of thoracic compartment, players often go in shock demanding prompt resuscitation. This paper investigates the thorax response of boxer being subject to lateral impact followed by Cardiopulmonary resuscitation (CPR). Due to complexity of thorax structure and materials, three dimensional finite element model in ANSYS was created to perform the computational biomechanical analysis of two-stage loading (i.e. lateral impact load and CPR forces). Model input parameters such as material, loading and boundary conditions have been defined. Post processing values such as deformations and stresses have been presented.

Impact Load Buffering Method Based on Stress Wave Attenuation Principle

2019 ◽  
Vol 11 (02) ◽  
pp. 1950019 ◽  
Author(s):  
Lin Gan ◽  
He Zhang ◽  
Cheng Zhou ◽  
Lin Liu
Keyword(s):  
Stress Wave ◽  
Wave Attenuation ◽  
Impact Load ◽  
Dynamics Simulation ◽  
Scanning System ◽  
Isolation Method ◽  
Element Analysis ◽  
System A ◽  
High Emission ◽  
The Impact

Rotating scanning motor is the important component of synchronous scanning laser fuze. High emission overload environment in the conventional ammunition has a serious impact on the reliability of the motor. Based on the theory that the buffer pad can attenuate the impact stress wave, a new motor buffering Isolation Method is proposed. The dynamical model of the new buffering isolation structure is established by ANSYS infinite element analysis software to do the nonlinear impact dynamics simulation of rotating scanning motor. The effectiveness of Buffering Isolation using different materials is comparatively analyzed. Finally, the Macht hammer impact experiment is done, the results show that in the experience of the 70,000[Formula: see text]g impact acceleration, the new buffering Isolation method can reduce the impact load about 15 times, which can effectively alleviate the plastic deformation of rotational scanning motor and improve the reliability of synchronization scanning system. A new method and theoretical basis of anti-high overload research for Laser Fuze is presented.

scholarly journals Flow-induced vibrations of a rotating cylinder in an arbitrary direction

2018 ◽  
Vol 860 ◽  
pp. 739-766 ◽  
Author(s):  
Rémi Bourguet
Keyword(s):  
Three Dimensional ◽  
Rotating Cylinder ◽  
The Body ◽  
Arbitrary Direction ◽  
Fast Rotation ◽  
Flow Past ◽  
Symmetrical Configuration ◽  
Wide Range ◽  
Flow Induced Vibrations ◽  
The Impact

The flow-induced vibrations of an elastically mounted circular cylinder, free to oscillate in an arbitrary direction and forced to rotate about its axis, are examined via two- and three-dimensional simulations, at a Reynolds number equal to 100, based on the body diameter and inflow velocity. The behaviour of the flow–structure system is investigated over the entire range of vibration directions, defined by the angle $\unicode[STIX]{x1D703}$ between the direction of the current and the direction of motion, a wide range of values of the reduced velocity $U^{\star }$ (inverse of the oscillator natural frequency) and three values of the rotation rate (ratio between the cylinder surface and inflow velocities), $\unicode[STIX]{x1D6FC}\in \{0,1,3\}$, in order to cover the reference non-rotating cylinder case, as well as typical slow and fast rotation cases. The oscillations of the non-rotating cylinder ($\unicode[STIX]{x1D6FC}=0$) develop under wake-body synchronization or lock-in, and their amplitude exhibits a bell-shaped evolution, typical of vortex-induced vibrations (VIV), as a function of $U^{\star }$. When $\unicode[STIX]{x1D703}$ is increased from $0^{\circ }$ to $90^{\circ }$ (or decreased from $180^{\circ }$ to $90^{\circ }$), the bell-shaped curve tends to monotonically increase in width and magnitude. For all angles, the flow past the non-rotating body is two-dimensional with formation of two counter-rotating spanwise vortices per cycle. The behaviour of the system remains globally the same for $\unicode[STIX]{x1D6FC}=1$. The principal effects of the slow rotation are a slight amplification of the VIV-like responses and widening of the vibration windows, as well as a limited asymmetry of the responses and forces about the symmetrical configuration $\unicode[STIX]{x1D703}=90^{\circ }$. The impact of the fast rotation ($\unicode[STIX]{x1D6FC}=3$) is more pronounced: VIV-like responses persist over a range of $\unicode[STIX]{x1D703}$ but, outside this range, the system is found to undergo a transition towards galloping-like oscillations characterised by amplitudes growing unboundedly with $U^{\star }$. A quasi-steady modelling of fluid forcing predicts the emergence of galloping-like responses as $\unicode[STIX]{x1D703}$ is varied, which suggests that they could be mainly driven by the mean flow. It, however, appears that flow unsteadiness and body motion remain synchronised in this vibration regime where a variety of multi-vortex wake patterns are uncovered. The interaction with flow dynamics results in deviations from the quasi-steady prediction. The successive steps in the evolution of the vibration amplitude versus $U^{\star }$, linked to wake pattern switch, are not captured by the quasi-steady approach. The flow past the rapidly-rotating, vibrating cylinder becomes three-dimensional over an interval of $\unicode[STIX]{x1D703}$ including the in-line oscillation configuration, with only a minor effect on the system behaviour.

scholarly journals New Design Procedure of Transtibial ProsthesisBed Stump Using Topological Optimization Method

Symmetry ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1837 ◽  
Author(s):  
Martin Sotola ◽  
David Stareczek ◽  
David Rybansky ◽  
Jiri Prokop ◽  
Pavel Marsalek
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Design Procedure ◽  
Optimization Method ◽  
Topological Optimization ◽  
Element Analysis ◽  
Current Application ◽  
Transtibial Prosthesis ◽  
Walking Biomechanics ◽  
The Impact

This paper presents a new design procedure for production of a transtibial prosthesis bed stump by three-dimensional (3D) printing with topological optimization. The suggested procedure combines the medical perspective with finite element analysis and facilitates regaining the symmetry in patients with transtibial prosthesis, which leads to life improvement. The particular focus of the study is the weight reduction of the lower part of the bed stump, while taking into account its stiffness and load-bearing capacity. The first part of the work deals with the analysis of the subject geometry of the bed stump, which is usually oversized in terms of the weight and stiffness that are necessary for the current application. In the second part, an analysis of walking biomechanics with a focus on the impact and rebound phases is presented. Based on the obtained information, a spatial model of the lower part of the bed stump is proposed in the third phase, in which the finite element method is described. In the fourth part, the topological optimization method is used for reducing the structure weight. In the last part, the results of the designed model are analyzed. Finally, the recommendations for the settings of the method are presented. The work is based on the practical industry requirements, and the obtained results will be reflected in the design of new types of transtibial prosthesis.

Finite-element analysis of multi-body contacts for pile driving using a hydraulic pile hammer

2011 ◽  
Vol 225 (5) ◽  
pp. 1153-1161 ◽  
Author(s):  
Y Guo ◽  
J P Hu ◽  
L Y Zhang
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Test Point ◽  
Pile Driving ◽  
Penalty Function Method ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Material Choice ◽  
Multi Body ◽  
The Impact

This article treats the pile driving as multi-body dynamic contacts. By using the penalty function method and three-dimensional model of finite-element method, the dynamic process of pile driving is acquired and a method for choosing the cushion material of the hydraulic pile hammer to improve driving efficiency is proposed. The process of pile driving in the real situation of an industrial experiment is simulated. The results of stress on test point are consistent with the test point. By analysing the stress distributed along the direction of pile radius and pile axis, the rule of the stress distribution on the pile is concluded. The rule for cushion material choice is obtained by comparing the influence for the impact stress with different elastic modulus ratio of the hammer cushion to the pile and the pile cushion to the pile.

Influence of Reference Conditions in the Analysis of the Impact of Flexible Bodies

2001 ◽  
Author(s):  
José L. Escalona ◽  
Juana Mayo ◽  
Jaime Domínguez
Keyword(s):  
Rigid Body ◽  
Reference Conditions ◽  
Normal Modes ◽  
Frame Of Reference ◽  
The Body ◽  
Natural Boundary Condition ◽  
Flexible Bodies ◽  
Free Interface ◽  
Fixed Interface ◽  
The Impact

Abstract In this paper, the floating frame of reference approach is applied to the dynamics of the impact of flexible bodies, while component mode synthesis is used to describe deformation. The influence of the reference conditions, that indicate the type of attachment between the body fixed frame of reference and the flexible bodies, is investigated. Rigid and free attachments allow the use of fixed interface and free interface normal modes, respectively. A finite number of fixed interface modes does not fulfil the natural boundary condition at the attachment point. Free interface normal modes cannot describe the compressive forces at the contact surface. However, it is shown that both set of modes are able to describe the impact-induced elastic waves. In the evaluation of the kinematic coefficient of restitution, these two approaches differ significantly. When free attachment is considered, the derivatives of the reference co-ordinates coincide with the equivalent rigid body velocities of the flexible bodies, remaining constant after the impact. However, if the body frame of reference is rigidly attached, the equivalent rigid body velocities of the flexible body have to be evaluated as a linear combination of the derivative of reference and elastic co-ordinates. The axial impact of a rigid body on a flexible rod and the transverse impact of a flexible pendulum with a fixed stop are simulated to illustrate these facts. Hertzian contact forces are assumed to occur during impact.

Thermomechanical Finite Element Analysis of Impact-Induced Magnetic Erasures in Magnetic Storage Thin Film Media

2007 ◽  
Author(s):  
Ning Yu ◽  
Andreas A. Polycarpou ◽  
Jorge V. Hanchi
Keyword(s):  
Finite Element ◽  
Hard Disk Drives ◽  
Three Dimensional ◽  
Thermal Response ◽  
Rotating Disk ◽  
Oblique Impact ◽  
Magnetic Storage ◽  
The Finite Element Method ◽  
Element Analysis ◽  
The Impact

Oblique impact of a slider with a rotating disk in hard disk drives was analyzed using the finite element method. A three dimensional, thermomechanical, impact model was developed to study the mechanical and thermal response during the impact of a spherical slider corner with the disk. The model was validated by comparing finite element results with analytical solutions for homogeneous glass disk under simple conditions. Impact penetration, stress and incurred flash temperature were obtained for various normal impact velocities.

Design of the SAFER Emergency Gate Using LS-DYNA

2005 ◽  
Author(s):  
Robert W. Bielenberg ◽  
John D. Rohde ◽  
John D. Reid
Keyword(s):  
Impact Load ◽  
High Strength ◽  
Full Scale ◽  
Element Analysis ◽  
Worst Case ◽  
Crash Testing ◽  
Additional Protection ◽  
Energy Absorbing ◽  
The Impact ◽  
Gate Design

In recent years, NASCAR and the Indy Racing League have improved the safety of their racetracks through the installation of the Steel And Foam Energy Reduction barrier (SAFER). The new barrier consists of a high-strength, tubular steel skin that distributes the impact load to energy-absorbing foam cartridges in order to reduce the severity of the impact, extends the impact event, and provides the occupant of the race car additional protection. During installation of the SAFER barrier, the designers realized that certain race tracks were designed with the emergency track exit in the outside of the corner. Because the SAFER barrier needed to be installed in these corners, a gate mechanism had to be designed for the barrier that would provide access to the track while retaining the safety performance of the system. Full-scale crash testing of the first SAFER gate design showed that the gate did not posses sufficient capacity to handle the loads experienced during a worst-case impact scenario. Non-linear finite element analysis was then used to redesign the gate mechanism. The original gate design was simulated using LS-DYNA in order to validate the computational model. Modifications to increase the capacity of the gate mechanism were designed and analyzed until suitable results were obtained through simulation. Finally, the redesigned SAFER gate was successfully full-scale crash tested.

Bionic Lubrication System of Artificial Joints: System Design and Mechanics Simulation

2005 ◽  
Author(s):  
S. H. Su ◽  
J. H. Zhang ◽  
D. H. Tao
Keyword(s):  
Three Dimensional ◽  
Joint Capsule ◽  
The Body ◽  
Artificial Joint ◽  
Lubrication System ◽  
Wear Particles ◽  
Element Analysis ◽  
Artificial Joints ◽  
Fea Model ◽  
Capsule Thickness

A new structure of artificial joints with bionic joint capsule was proposed and designed to overcome the feedback of current prostheses that omitted many functions of lubricant and joint capsule. The new structure was composed of three components: therapeutic lubricant, artificial joints and artificial joint capsule. The lubricant sealed by capsule not only can reduce the wear of artificial joints but also can prohibit the wear particles leaking to the body liquid. So the unwilling reactions between the wear particles and liquid may be avoided completely. Meanwhile, a three-dimensional (3-D) finite element analysis (FEA) model was created for the bionic artificial joints with joint capsule. The effects of capsule thickness and the flexion angels on the stress values and distributions were discussed in detail.

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