Impact of a Fixed-Length Rigid Cylinder on an Elastic-Plastic Homogeneous Body

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Raja R. Katta ◽  
Andreas A. Polycarpou
Keyword(s):  
Impact Damage ◽  
Element Model ◽  
Elastic Behavior ◽  
Magnetic Storage ◽  
Practical Case ◽  
Homogeneous Body ◽  
Rigid Cylinder ◽  
Elastic Plastic ◽  
Fixed Length ◽  
The Impact

A contact mechanics (CM) based model of a fixed-length rigid cylinder impacting a homogeneous elastic-plastic homogeneous body was developed and includes an improved method of estimating the residual depth after impact. The nonlinear elastic behavior during unloading was accounted for to develop an improved coefficient of restitution model. The impact model was applied to study a practical case of a cylindrical feature on the slider of a magnetic storage hard disk drive impacting the disk to predict various critical impact contact parameters. The CM model was validated using a plane strain finite element model and it was found that a cylindrical feature with a longer length results in a substantial alleviation of impact damage.

Simulation of Impact Damage in Foam-Based Sandwich Composites

2013 ◽  
Vol 569-570 ◽  
pp. 25-32
Author(s):  
Dian Shi Feng ◽  
Francesco Aymerich
Keyword(s):  
Impact Damage ◽  
Element Model ◽  
Fracture Mechanisms ◽  
Sandwich Composites ◽  
Typically Developing ◽  
Damage Resistance ◽  
Damage And Fracture ◽  
Closed Cell ◽  
Impact Energies ◽  
The Impact

The paper describes the application of a 3D finite element model for prediction of impact induced damage in sandwich composites consisting of laminated skins bonded to a closed cell foam core. The major damage and fracture mechanisms typically developing in transversally loaded sandwich composites were simulated in the model. The model was implemented in the FE package ABAQUS/Explicit and used to predict the impact damage resistance of sandwich panels with different core densities, core thicknesses, and skins layups. Numerical results obtained by FE simulations were compared with experimental data and observations collected through impact tests carried out at various impact energies.

High Velocity Oblique Impact and Coefficient of Restitution for Head Disk Interface Operational Shock

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Raja R. Katta ◽  
Andreas A. Polycarpou ◽  
Jorge V. Hanchi ◽  
Robert M. Crone
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Impact Damage ◽  
Element Model ◽  
Oblique Impact ◽  
Coefficient Of Restitution ◽  
Energy Losses ◽  
Elastic Plastic ◽  
Impact Angles ◽  
Operational Shock

With the increased use of hard disk drives (HDDs) in mobile and consumer applications combined with the requirement of higher areal density, there is enhanced focus on reducing head disk spacing, and consequently there is higher susceptibility of slider/disk impact damage during HDD operation. To investigate this impact process, a dynamic elastic-plastic finite element model of a sphere (representing a slider corner) obliquely impacting a thin-film disk was created to study the effect of the slider corner radius and the impact velocity on critical contact parameters. To characterize the energy losses due to the operational shock impact damage, the coefficient of restitution for oblique elastic-plastic impact was studied using the finite element model. A modification to an existing physics-based elastic-plastic oblique impact coefficient of restitution model was proposed to accurately predict the energy losses for a rigid sphere impacting a half-space. The analytical model results compared favorably to the finite element results for the range from low impact angles (primarily normal impacts) to high impact angles (primarily tangential impacts).

Elastic/Plastic Contact Mechanics-Based Analysis of Hard Disk Drive Media Damage From Slider Corner Impacts

2007 ◽  
Author(s):  
Raja R. Katta ◽  
Andreas A. Polycarpou ◽  
Jorge V. Hanchi
Keyword(s):  
Thin Film ◽  
Contact Mechanics ◽  
Impact Damage ◽  
Disk Drive ◽  
High Impact ◽  
Impact Model ◽  
Elastic Plastic ◽  
The Impact ◽  
Contact Parameters ◽  
Very High

A contact mechanics-based elastic-plastic impact model which considers slider corner – head disk interaction has been proposed. This model estimates the impact contact parameters accounting for the plastic deformation effects of the realistic thin-film disk media. These properties were utilized for the elastic-plastic impact model to estimate the contact parameters. Very high impact velocities and/or small slider corner radii resulted is extremely high contact depths where the disk substrate mostly dominated the impact and the effect of layers could not be seen. At lower impact velocities and higher corner radii, the impact damage was relatively smaller. The effect of the thin-film layers, which are stiffer than the substrate, was clearly observed.

scholarly journals Impact Damage Characteristics of Carbon Fibre Metal Laminates: Experiments and Simulation

2020 ◽  
Vol 27 (5) ◽  
pp. 511-531
Author(s):  
Y. Shi ◽  
C. Pinna ◽  
C. Soutis
Keyword(s):  
Carbon Fibre ◽  
Impact Damage ◽  
Fibre Composite ◽  
Element Model ◽  
Fibre Metal Laminates ◽  
Composite Layers ◽  
Fibre Metal ◽  
Improved Design ◽  
Cohesive Zone Elements ◽  
The Impact

Abstract In this work, the impact response of carbon fibre metal laminates (FMLs) was experimentally and numerically studied with an improved design of the fibre composite lay-up for optimal mechanical properties and damage resistance. Two different stacking sequences (Carall 3–3/2–0.5 and Carall 5–3/2–0.5) were designed and characterised. Damage at relatively low energy impact energies (≤30 J) was investigated using Ultrasonic C-scanning and X–ray Computed Tomography (X-RCT). A 3D finite element model was developed to simulate the impact induced damage in both metal and composite layers using Abaqus/Explicit. Cohesive zone elements were introduced to capture delamination occurring between carbon fibre/epoxy plies and debonding at the interfaces between aluminium and the composite layers. Carall 5–3/2–0.5 was found to absorb more energy elastically, which indicates better resistance to damage. A good agreement is obtained between the numerically predicted results and experimental measurements in terms of force and absorbed energy during impact where the damage modes such as delamination was well simulated when compared to non-destructive techniques (NDT).

Study on Finite Element Model for Impact Damage of Composite Structure

2015 ◽  
Vol 752-753 ◽  
pp. 769-772
Author(s):  
Hyun Bum Park
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Composite Structure ◽  
Sandwich Structure ◽  
Impact Analysis ◽  
Impact Damage ◽  
Element Model ◽  
Sandwich Composite ◽  
The Impact ◽  
Element Method

In this work, study on impact damage FEM model of composite sandwich structure was performed. Sandwich structure configuration is made of carbon-epoxy face sheets and foam cores. From the finite element method analysis results of sandwich composite structure, it was confirmed that the results of analysis was reasonable. The velocity of impactor to initiate damage was estimated, and in order to investigate the damage at the predicted velocity, impact analysis using finite element method was performed. According to the impact analysis results of sandwich structure, it was confirmed that the damage was generated at the estimated impact velocity. Finally, the comparison of the numerical results with those measured by the experiment showed good agreement.

scholarly journals Characterization and Imaging of Localized Thickness Loss in GFRP with Ka-Band Microwave Open-Ended Waveguides

2020 ◽  
Author(s):  
Jinhua Hu ◽  
Yong Li ◽  
Jianguo Tan ◽  
Wenjia Li ◽  
Zhenmao Chen
Keyword(s):  
Ultrasonic Testing ◽  
Impact Damage ◽  
Element Model ◽  
Fibre Reinforcement ◽  
Destructive Testing ◽  
Ka Band ◽  
Thickness Loss ◽  
Set Up ◽  
The Impact ◽  
Non Destructive

Glass Fibre Reinforcement Plastic (GFRP) is widely used in engineering fields including aerospace, marine and construction, etc. During practical service, it is prone to the impact damage leading to the Localized Thickness Loss (LTL) which severely influences the integrity and safety of GFRP. To detect and evaluate LTL in GFRP, common Non-Destructive Testing (NDT) techniques such as ultrasonic testing and thermography are usually applied. Complementary to these methods, microwave NDT has been found to be one of the promising techniques in quantitative evaluation of GFRP. In this paper, the characterization and imaging of LTL in GFRP by microwave NDT are intensively investigated. A 2D Finite Element Model (FEM) with the Ka-band open-ended waveguide and GFRP sample subject to LTL has been set up and adopted for analysis of field characteristics and testing signals. Following that, an experimental investigation is conducted to further study the feasibility of LTL imaging by microwave NDT with the Ka-band open-ended waveguide. The results from simulations and experiments indicate the applicability of Ka-band microwave open-ended waveguide for detection and evaluation of LTL in GFRP.

Thermoelastic Instability in an Automatic Transmission Clutch With a “Finger” Piston

2005 ◽  
Author(s):  
Przemyslaw Zagrodzki ◽  
Wenping Zhao
Keyword(s):  
Finite Element ◽  
Hot Spots ◽  
Automatic Transmission ◽  
Element Model ◽  
Elastic Behavior ◽  
Practical Case ◽  
Thermoelastic Instability ◽  
Automotive Transmission ◽  
Friction Clutch ◽  
Theoretical Results

An important practical case of frictionally excited thermoelastic instability (TEI) in a wet multidisk friction clutch of an automotive transmission that includes so-called finger piston is investigated. Advanced finite element model of thermoelastic multi-surface contact problem is used. Theoretical results are verified experimentally. The study shows that the finger piston used in transmission clutches can trigger unstable thermo elastic behavior which leads to severe hot spots.

Virtual Impact Test for Aluminum-Alloy Wheel Based on Numerical Simulation Method

2012 ◽  
Vol 457-458 ◽  
pp. 93-97 ◽  
Author(s):  
Ji Gang Chen ◽  
Guo Zhi Zhang
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Aluminum Alloy ◽  
Impact Test ◽  
High Reliability ◽  
Element Model ◽  
Practical Case ◽  
Virtual Design ◽  
Alloy Wheel ◽  
The Impact

The mechanical properties of car wheel mast have high reliability requirements. The impact test for trial casting aluminum alloy wheel must be passed, which is one of the bench tests. Based the practical case, the integrated finite-element model for virtual test is established, including impact block, wheel, tire, bracket, rubber pad, the standard test load conditions are imposed, and the entire impact process was simulated by finite-element method, the velocity, displacement and kinetic energy curves of the impact block, the stress distribution and the impact force curve of change were obtained. Moreover, using in a typical case, compared with the physical impact test, the model and procedure of the finite-element numerical simulation was verified. The modeling method and calculation procedure given can guide the virtual design of aluminum-alloy wheel, the blindness of design can be reduced, and the development work efficiency can be increased.

Analytical and Experimental Elastic-Plastic Impact Analysis of a Magnetic Storage Head-Disk Interface

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Raja R. Katta ◽  
Andreas A. Polycarpou ◽  
Jorge V. Hanchi ◽  
Mallika Roy
Keyword(s):  
Thin Film ◽  
Impact Analysis ◽  
Hard Disk Drives ◽  
Rigid Sphere ◽  
Magnetic Storage ◽  
Impact Model ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Elastic Plastic ◽  
The Impact

As the use of hard disk drives in mobile applications increases, the susceptibility of disk damage due to high velocity slider-disk impact presents a serious challenge. The impact could result in extremely high contact stresses, leading to the failure of the head-disk interface. An elastic-plastic contact-mechanics-based impact model was developed and implemented to study the impact between a slider corner and a disk. The impact model is based on the contact of a rigid sphere on a deformable half-space. The effect of slider corner radii and impact velocities on the contact parameters was initially investigated for a homogeneous disk substrate. To examine the effects of thin-film layers on the disk, the model was extended to a realistic layered disk, where the actual layered mechanical properties were directly measured. At high impact velocities and/or small slider corner radii, the impact was found to be dominated by the substrate and the effect of layers was negligible. At low impact velocities and/or large slider corner radii, the effect of nanometer thick layers could be clearly seen, as these layers are stiffer than the substrate protecting the disk from potential damage at lighter loads. Realistic dynamic impact experiments involving a slider and a spinning thin-film disk were performed using an operational shock tester. The impact damage was characterized in terms of residual penetration depth caused by the impact force of the shock and the impact velocity of the slider. However, the results were inconclusive in correlating with the impact model. To better control the experimental parameters, quasistatic nanoindentation experiments were performed on actual thin-film media and were successfully compared with the model predictions.

scholarly journals Influence of Location and Thickness Variations on Guided Waves in Defective Carbon/Epoxy Plate

2019 ◽  
Vol 9 (1) ◽  
pp. 5736-5740
Keyword(s):  
Guided Waves ◽  
Wave Attenuation ◽  
Impact Damage ◽  
Plate Thickness ◽  
Element Model ◽  
Guided Wave ◽  
Ultrasonic Waves ◽  
Time Signal ◽  
Matrix Cracks ◽  
The Impact

This paper addresses the effects of plate thickness and defect location on guided wave propagation in carbon/epoxy plates. A three-dimensional (3D) finite element model (FEM) of the plate was developed using MATLAB program codes, and simulated in Abaqus/Explicit. Referring to experimental ultrasonic C-scan images, the complex impact damage was modelled with irregular-shaped delamination and through-thickness matrix cracks. The simulated results show that a slower arrival time signal and amplitude drop of guided wave captured behind the defective region can be used as an indicator of the impact damage. A largOer scattering occurred when delamination was located closer to the plate surface. The extent of scattering gets larger, especially in the direction of 345o from the excitation point. It is also observed that the impact damage can still be detected through a line scan method across the impact damage, although the wave attenuation is greater in a thicker composite plate. By investigating these factors independently, the trends of the scattered guided ultrasonic waves can be classified and perhaps will revolutionize a smart non-destructive method for composite structure in the future.

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