Predicting the Peen Forming Effectiveness of Ti-6Al-4V Strips With Different Thicknesses Using Realistic Finite Element Simulations

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Fan Yang ◽  
Yukui Gao
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Residual Stress Distribution ◽  
Strip Thickness ◽  
Thin Strip ◽  
Fe Model ◽  
Rate Dependent ◽  
Peen Forming ◽  
Proposed Model ◽  
The Relationship

This paper is intended to quantify the relationship between the peen forming effectiveness and various involved parameters through a realistic numerical study. For this purpose, a new finite element (FE) model is proposed with full geometry representation, random shots generation, and rate-dependent material law of kinematic strain-hardening. The mesh sensitivity and effects of boundary conditions are carefully examined. The FE model is validated by comparing the results with the experimental measurements. The proposed model is then used to investigate the effects of the peening intensity (represented as the shot velocity) and the strip thickness on the peen-formed deflection and the residual stress distribution for strips made of Ti-6Al-4V. Our results indicate the existence of a maximum convex deflection for different strip thicknesses. In addition, a reversed deflection (i.e., concaved curvature) is observed for severe peening conditions (i.e., thin strip under high peening intensity). Our simulations verify the previous proposition that a concaved curvature can be generated only when the whole cross section is plastically deformed.

Realistic Finite Element Simulations of Arc-Height Development in Shot-Peened Almen Strips

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Zhuo Chen ◽  
Fan Yang ◽  
S. A. Meguid
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Equivalent Plastic Strain ◽  
Fe Model ◽  
Residual Stress Field ◽  
Fe Method ◽  
Rate Dependent ◽  
Peen Forming ◽  
Underlying Mechanisms ◽  
Explicit Dynamic

It is the objective of this study to conduct realistic simulations of the arc-height development in shot-peened Almen strips using the finite element (FE) method. Unlike our earlier work which is devoted to relaxation of shot peening induced residual stress, in this paper, the focus is on peen forming as a result of repeated spherical impingement. Specifically, a 3D FE model with 1500 randomly distributed shots bombarding an Almen strip was developed. Strain rate dependent plasticity was considered and an artificial material damping was applied to control the undesired high-frequency oscillations. The solution further adopts both explicit dynamic and implicit quasi-static analyses to simulate the entire arc-height development in the Almen strips. Quantitative relationships between the resulting equivalent plastic strain and the associated residual stress distribution for a given shot velocity and shot numbers are established and discussed. The work also considers the effect of repeated impacts upon the induced residual stress field using a large number of random shots. Attention was further devoted to the effect of the strip constraint upon the outcome of the impingement. Our results indicate that the proposed FE model is a powerful tool in investigating the underlying mechanisms of the peening treatment.

scholarly journals Design and analysis of concrete-filled tubular flange girders under combined loading

2021 ◽  
pp. 136943322110015
Author(s):  
Rana Al-Dujele ◽  
Katherine Ann Cashell
Keyword(s):  
Finite Element ◽  
Axial Force ◽  
Failure Modes ◽  
Numerical Study ◽  
Combined Loading ◽  
Torsional Stiffness ◽  
Fe Model ◽  
Combined Effects ◽  
Element Analysis ◽  
Hollow Section

This paper is concerned with the behaviour of concrete-filled tubular flange girders (CFTFGs) under the combination of bending and tensile axial force. CFTFG is a relatively new structural solution comprising a steel beam in which the compression flange plate is replaced with a concrete-filled hollow section to create an efficient and effective load-carrying solution. These members have very high torsional stiffness and lateral torsional buckling strength in comparison with conventional steel I-girders of similar depth, width and steel weight and are there-fore capable of carrying very heavy loads over long spans. Current design codes do not explicitly include guidance for the design of these members, which are asymmetric in nature under the combined effects of tension and bending. The current paper presents a numerical study into the behaviour of CFTFGs under the combined effects of positive bending and axial tension. The study includes different loading combinations and the associated failure modes are identified and discussed. To facilitate this study, a finite element (FE) model is developed using the ABAQUS software which is capable of capturing both the geometric and material nonlinearities of the behaviour. Based on the results of finite element analysis, the moment–axial force interaction relationship is presented and a simplified equation is proposed for the design of CFTFGs under combined bending and tensile axial force.

J-Integral Analysis of Surface Cracks in Round Bars under Bending Moments

2011 ◽  
Vol 52-54 ◽  
pp. 43-48 ◽  
Author(s):  
Al Emran Ismail ◽  
Ahmad Kamal Ariffin ◽  
Shahrum Abdullah ◽  
Mariyam Jameelah Ghazali ◽  
Ruslizam Daud
Keyword(s):  
Finite Element ◽  
Crack Depth ◽  
Crack Tip ◽  
Bending Moment ◽  
Limit Load ◽  
Fe Model ◽  
Surface Cracks ◽  
Element Analysis ◽  
Reference Stress ◽  
Proposed Model

This paper presents a non-linear numerical investigation of surface cracks in round bars under bending moment by using ANSYS finite element analysis (FEA). Due to the symmetrical analysis, only quarter finite element (FE) model was constructed and special attention was given at the crack tip of the cracks. The surface cracks were characterized by the dimensionless crack aspect ratio, a/b = 0.6, 0.8, 1.0 and 1.2, while the dimensionless relative crack depth, a/D = 0.1, 0.2 and 0.3. The square-root singularity of stresses and strains was modeled by shifting the mid-point nodes to the quarter-point locations close to the crack tip. The proposed model was validated with the existing model before any further analysis. The elastic-plastic analysis under remotely applied bending moment was assumed to follow the Ramberg-Osgood relation with n = 5 and 10. J values were determined for all positions along the crack front and then, the limit load was predicted using the J values obtained from FEA through the reference stress method.

A Method for FE Model Updating of Coupled Vibro-Acoustic Systems Using Constrained Optimization

2013 ◽  
Author(s):  
D. V. Nehete ◽  
S. V. Modak ◽  
K. Gupta
Keyword(s):  
Finite Element ◽  
Constrained Optimization ◽  
Model Updating ◽  
Numerical Study ◽  
Element Model ◽  
Rectangular Cavity ◽  
Mode Shapes ◽  
Fe Model ◽  
Structural Dynamic ◽  
Fe Model Updating

Finite element (FE) model updating is now recognized as an effective approach to reduce modeling inaccuracies present in an FE model. FE model updating has been researched and studied well for updating FE models of purely structural dynamic systems. However there exists another class of systems known as vibro-acoustics in which acoustic response is generated in a medium due to the vibration of enclosing structure. Such systems are commonly found in aerospace, automotive and other transportation applications. Vibro-acoustic FE modeling is essential for sound acoustic design of these systems. Vibro-acoustic system, in contrast to purely structural system, has not received sufficient attention from FE model updating perspective and hence forms the topic of present paper. In the present paper, a method for finite element model updating of coupled structural acoustic model, constituted as a problem of constrained optimization, is proposed. An objective function quantifying error in the coupled natural frequencies and mode shapes is minimized to estimate the chosen uncertain parameters of the system. The effectiveness of the proposed method is validated through a numerical study on a 3D rectangular cavity attached to a flexible panel. The material property and the stiffness of joints between the panel and rectangular cavity are used as updating parameters. Robustness of the proposed method under presence of noise is investigated. It is seen that the method is not only able to obtain a close match between FE model and corresponding ‘measured’ vibro-acoustic characteristics but is also able to estimate the correction factors to the updating parameters with reasonable accuracy.

scholarly journals A Simplified Finite Element Approach for Modeling of Multilayer Plates

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Taiyou Liu ◽  
Xinbo Ma ◽  
Pak Kin Wong ◽  
Jing Zhao ◽  
Zhengchao Xie ◽  
...  
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Reference Value ◽  
Fe Model ◽  
Practical Applications ◽  
Aerospace Applications ◽  
Equivalent Bending Stiffness ◽  
Element Approach ◽  
Set Up ◽  
Transverse Response

The multilayer plate has a great potential for automotive and aerospace applications. However, the complexity in structure and calculation of the response impede the practical applications of multilayer plates. To solve this problem, this work proposes a new plate finite element and a simplified finite element (FE) model for multilayer plates. The proposed new plate finite element consists of the shear and extension strains in all layers. The multilayer structure with the proposed new plate finite element is regarded as a reference to calculate the reference value of the transverse response. The simplified FE model of multilayer plates is proposed based on the equivalent bending stiffness by curve fitting of the reference value of the transverse response. Numerical study shows that this approach can be used to set up the simplified FE model of multilayer plates.

scholarly journals NUMERICAL STUDY ON EFFECTS OF TENON SIZES ON WITHDRAWAL LOAD CAPACITY OF MORTISE AND TENON JOINT

Wood Research ◽  
2021 ◽  
Vol 66 (2) ◽  
pp. 321-330
Author(s):  
Tianxing Zhang ◽  
Wengang Hu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Response Surface ◽  
Numerical Study ◽  
Load Capacity ◽  
The Finite Element Method ◽  
Surface Method ◽  
Mortise And Tenon ◽  
Relationship Of ◽  
The Relationship

The effect of tenon length and tenon width on withdrawal load capacity of mortise and tenon (M-T) joint was studied based on the finite element method (FEM), and the relationship of withdrawal load capacity relating to tenon length and tenon width was regressed using response surface method. The results showed that the tenon length and tenon width had remarkable effects on withdrawal load capacity of M-T joint T-shaped sample. The effect of tenon length on withdrawal load capacity was greater than tenon width. The regression equation used to predict the withdrawal load capacity was capable of optimizing the tenon sizes of M-T joint with R-square of 0.926. Using FEM can get more knowledge of M-T joint visually, and reduce the costs of materials and time of experiments.

Experimental and Numerical Study on Crashworthiness Parameters of Mild Steel Square Tube under Quasi-Static Axial Compression

2020 ◽  
Vol 12 (2) ◽  
Author(s):  
Shinde Rushikesh ◽  
Mali Kiran ◽  
M. Kathiresan ◽  
Kulkarni Dhananjay
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Experimental Testing ◽  
Testing Machine ◽  
Fe Analysis ◽  
Fe Model ◽  
Element Analysis ◽  
Static Test ◽  
Collapse Mode ◽  
Crash Behaviour

In the present research, an experimental and numerical study on the crush response of square tube is presented. The explicit Finite Element Analysis (FEA) in LS-DYNA software is carried out to simulate crash behaviour under the quasi-static test conditions. Compression load is applied quasi-statically in an experimental study on the square tube specimens using Universal Testing Machine (UTM). In quasi-static test the bottom platen speed used is 1 mm/min. From experimental testing symmetric collapse mode is observed in all deformed specimens. The development of the symmetric collapse mode in a Finite Element (FE) model is also observed. Thus fold formation and crush response predicted by FE analysis are observed to be in very good correlation with the results obtained from experimental testing. Furthermore, the effect of the thickness of tube on crashworthiness parameters is investigated. From the FE analysis, it is found that the thickness of the square tube influences significantly the crashworthiness parameters.

scholarly journals Influence of Grains Shape Irregularity in Porous Ceramics—Numerical Study

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1944
Author(s):  
Danuta Miedzińska
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Computer Code ◽  
Porous Ceramics ◽  
Ceramic Foam ◽  
Fe Model ◽  
Strength Behavior ◽  
Absorbing Material ◽  
Shape Irregularity ◽  
Energy Absorbing

The presented study deals with the analysis of the stochastic geometry of grains on ceramic foam strength behavior. A microstructural finite element (FE) model of a grainy structure of such a material was developed and stochastic changes to the grain geometry (initially of a regular cubic shape) were introduced. The numerical compression test of a series of finite element models was carried out with the use of LS Dyna computer code. To consider the ceramic specific behavior, the Johnson Holmquist constitutive model was implemented with parameters for alumina. The influence of the stochastic irregularities on the ceramic foam strength was observed—the geometry changes caused an increase in the maximum stress, which could be the basis for the indication that the production of the energy absorbing material should be based on mostly irregular grains.

Ductile Failure Prediction of Spot Welded Lap Joint

2012 ◽  
Vol 165 ◽  
pp. 285-289 ◽  
Author(s):  
A.A. Borhana ◽  
A.T. Mohamad ◽  
A. Abdul-Latif ◽  
Z. Ahmad ◽  
A. Ayob ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Triaxiality ◽  
Ductile Failure ◽  
Material Damage ◽  
Fe Model ◽  
Lap Joint ◽  
Damage Initiation ◽  
Localized Necking ◽  
The Relationship ◽  
Spot Welded

A finite element (FE) model incorporating a progressive material damage with Rice-Tracey damage initiation criterion is developed in this study. The relationship between local ductility reduction and stress triaxiality was established experimentally. The FE model was validated by comparisons of load-displacement response of the spot welded lap joint specimen at displacement rate of 5 mm/min and the observed ductile failure mechanism. Results show that Rice-Tracey damage initiation criterion used is sufficient to reproduce the observed ductile failure response of the specimen. Failure of the spot welded lap joint is initiated at the HAZ/fusion zone interface with localized necking.

A Numerical Study on Hollow Droplets Impact onto a Solid Substrate

2014 ◽  
Vol 852 ◽  
pp. 501-505
Author(s):  
Da Shu Li ◽  
Xing Qi Qiu ◽  
Zhi Wei Zheng
Keyword(s):  
Transfer Rate ◽  
Flat Surface ◽  
Numerical Study ◽  
Solid Substrate ◽  
Hydrodynamic Characteristics ◽  
Air Entrapment ◽  
Deposition Parameters ◽  
Proposed Model ◽  
Gas Cavity ◽  
The Relationship

A numerical model using VOF method is developed to describe the phenomenon of a hollow droplet impact on a flat surface including spreading, retardation, recoil and first and secondary break up. The proposed model is verified by literature experiments. Some new hydrodynamic characteristics have been found. The mechanism of central counter jet is explored according to pressure distribution and velocity vectors inside droplet. The relationship between impact features of droplet and deposition parameters is highlighted. In order to investigate the heat transfer rate at the gas-liquid interface, air entrapment and gas cavity are discussed.

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