An Evaluation Index for Estimating Defeaturing-Induced Impacts on Finite Element Analysis

2009 ◽  
Author(s):  
Jianguo Tang ◽  
Shuming Gao ◽  
Hongwei Lin ◽  
Yusheng Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fe Analysis ◽  
Evaluation Index ◽  
Reciprocal Theorem ◽  
Element Analysis ◽  
Efficient Calculation ◽  
Practical Evaluation ◽  
The Difference ◽  
The Reciprocal Theorem

Defeaturing is a popular CAD/CAE simplification technique. However, defeaturing inevitably leads to errors that can not be effectively evaluated yet during a FE (Finite Element) analysis. In this paper, a novel evaluation index based on the reciprocal theorem is proposed to effectively and efficiently estimate defeaturing-induced impacts on FE analysis. Instead of using the difference of strain energy, the proposed evaluation index uses the difference of work to quantify the defeaturing-induced impacts on FE analysis so that it is not only effective but also can be efficiently calculated. In order for an efficient calculation of the evaluation index, a practical evaluation index is further derived from the proposed theoretical index, and its calculation method is given. The practical evaluation index has been applied to FE static computation of linear elastic structures. Therefore, we are able to adapt the simplification of a model according to a desired accuracy of the analysis results.

Validation of Nitinol SMA Characteristics Using Finite Element Analysis and Closed Form Solutions

2013 ◽  
Vol 856 ◽  
pp. 147-152
Author(s):  
S.H. Adarsh ◽  
U.S. Mallikarjun
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Closed Form ◽  
Closed Form Solution ◽  
Form Solution ◽  
Fe Analysis ◽  
Element Analysis ◽  
Complex Behaviour ◽  
Closed Form Solutions

Shape Memory Alloys (SMA) are promising materials for actuation in space applications, because of the relatively large deformations and forces that they offer. However, their complex behaviour and interaction of several physical domains (electrical, thermal and mechanical), the study of SMA behaviour is a challenging field. Present work aims at correlating the Finite Element (FE) analysis of SMA with closed form solutions and experimental data. Though sufficient literature is available on closed form solution of SMA, not much detail is available on the Finite element Analysis. In the present work an attempt is made for characterization of SMA through solving the governing equations by established closed form solution, and finally correlating FE results with these data. Extensive experiments were conducted on 0.3mm diameter NiTinol SMA wire at various temperatures and stress conditions and these results were compared with FE analysis conducted using MSC.Marc. A comparison of results from finite element analysis with the experimental data exhibits fairly good agreement.

A Comparative Study on Mechanical Behavior of Pipe-Socket Threaded Joints With Taper-Taper Threads and Taper-Parallel Threads Combinations by Finite Element Analysis and Experiments

2018 ◽  
Author(s):  
Satoshi Nagata ◽  
Shinichi Fujita ◽  
Toshiyuki Sawa
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Service Condition ◽  
Internal Thread ◽  
Element Analysis ◽  
Strain Pattern ◽  
External Thread ◽  
Thread Length ◽  
The Difference

There are two types of combination between external and internal threads used in threaded pipe connections for pressure piping specified in industrial standards like JIS as well as ISO. One is the combination that taper external thread of pipe is engaged with taper internal thread of a fitting. The other is that taper external thread of pipe is engaged with parallel internal thread of a fitting. Taper thread is always used for external thread outside the pipe wall. Both taper thread and parallel one are applicable to internal thread inside the fittings. This paper evaluates the mechanical behaviors of threaded pipe-socket joints (or pipe-coupling joints) and the difference due to the thread type combinations by means of axisymmetric finite element analysis for 3/4” and 3” joints. The analysis shows that the taper-taper threads combination establishes the full-length contact over the engaged threads but the taper-parallel has only a pair of threads in contact at the 1st engaged thread from the end of socket, and the difference results in the different behaviors of the joints. Stress and strain pattern also completely differ due to the difference in the engaged thread length. No significant effect of the size has been found in the present analysis for 3/4”and 3” joints. Experimental tightening tests and pressure leak tests have also been carried out for 3/4” and 3” joints with taper-taper threads combination. The measured experimental stress for 3/4” joints has shown an agreement with the simulated one fairly well. The pressure leak tests have demonstrated that the taper-taper threaded pipe-socket joints can hold internal pressure without leakage without using thread seal tape or jointing compound under low-pressure service condition. The 3/4” joints have started leaking at 1–4MPaG of internal pressure. The 3” joints haven’t shown leakage even at 6MPaG of internal pressure applied.

Finite Element Analysis (FEA) of Honeycomb Sandwich Panel for Continuum Properties Evaluation and Core Height Influence on the Dynamic Behavior

2011 ◽  
Vol 326 ◽  
pp. 1-10 ◽  
Author(s):  
Hammad Rahman ◽  
Rehan Jamshed ◽  
Haris Hameed ◽  
Sajid Raza
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Analytical Solution ◽  
Vibration Analysis ◽  
Sandwich Structure ◽  
Sandwich Panel ◽  
Fe Analysis ◽  
Element Analysis ◽  
Honeycomb Sandwich ◽  
Core Height

Finite element analysis of honeycomb sandwich panel has been performed by modeling the structure through three different approaches. Continuum properties are calculated through analytical solution and verified through FE analysis of bare core. In addition to that the thickness of core has also been varied in all the three approaches in order to study its effect on vibration analysis of sandwich structure.

scholarly journals Dynamic Response of a Laminated Plate With Friction Damping

1985 ◽  
Vol 107 (4) ◽  
pp. 375-377 ◽  
Author(s):  
Shen Zhong Han
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Resonant Frequency ◽  
Laminated Plates ◽  
Laminated Plate ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Solid Plate ◽  
Sandwich Type ◽  
The Difference

A sandwich-type plate with metal facings and felt core, fastened by bolts, was studied using both test and finite-element analysis. This type of plate is cheap, light, damping-effective and without pollution; therefore, it is widely used in astronautical engineering. The tests were conducted for different felt thicknesses, bolt numbers, and fastening forces. The results show that the damping depends on friction between the plates and the felt. As compared with an identical stiffness solid plate, the damping of laminated plates can be increased up to 30 times. A mesh with rectangular elements was adopted in the finite-element analysis. In accordance with the slipping mechanism, a rectangular plate clamped on one edge was analyzed with the foregoing elements to determine the resonant frequency and the damping. The difference between the calculated and tested results was within 5 percent for the resonant frequency.

Finite Element Analysis and Design of a Horizontal Tank on Saddle Supports

2002 ◽  
Author(s):  
Afewerki H. Birhane ◽  
Yogeshwar Hari
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Code Design ◽  
Element Analysis ◽  
Analysis And Design ◽  
Finite Element Software ◽  
Asme Code ◽  
Design Function ◽  
Horizontal Tank ◽  
The Difference

The objective of this paper is to design and analyze a horizontal tank on saddle supports. The horizontal vessel is to store various chemicals used in today’s industry. The over all dimensions of the horizontal vessel are determined from the capacity of the stored chemicals. These dimensions are first determined. The design function is performed using the ASME Code Sec VIII Div 1. The horizontal tank design is broken up into (a) shell design, (b) two elliptical heads and (c) two saddle supports. The designed dimensions are used to recalculate the stresses for the horizontal vessel. The dimensioned horizontal vessel with saddle supports and the saddle support structure is modeled using STAAD III finite element software. The stresses from the finite element software are compared with the stresses obtained from calculated stresses by ASME Code Sec VIII Div 1 and L. P. Zick’s analysis printed in 1951. The difference in the stress value is explained. This paper’s main objective is to compare the code design to the finite element analysis. The design is found to be safe for the specific configuration considered.

Distortion Simulation of Unsymmetrical Composite Laminates Using the Finite Element Analysis Method

2007 ◽  
Vol 546-549 ◽  
pp. 1563-1566
Author(s):  
Min Li ◽  
Bao Yan Zhang ◽  
Xiang Bao Chen
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Laminates ◽  
Shell Element ◽  
Element Analysis ◽  
Unsymmetric Laminates ◽  
The Finite Element Analysis ◽  
Simulation Results ◽  
The Difference

Unsymmetric composite laminates were benefit to reducing the structure weight of some aircrafts. However, the cured unsymmetric laminates showed distortion at room temperature. Therefore, predicting the deformation before using the unsymmetrical composite is very important. In this study an attempt was made to predict the shapes of some unsymmetric cross-ply laminates using the finite element analysis (FEA). The bilinear shell-element was adopted in the process. Then the simulation results were compared with the experimental data. The studies we had performed showed that the theoretical calculation agreed well with the experimental results, the predicted shapes were similar to the real laminates, and the difference between the calculated maximum deflections and the experimental data were less than 5%. Hence the FEA method was suitable for predicting the warpage of unsymmetric laminates. The error analysis showed that the simulation results were very sensitive to the lamina thickness, 2 α and (T.

Prediction of Closure Bolt Loads in Small Pressure Vessels: NUREG/CR-6007 vs. Detailed Finite Element Analysis

2010 ◽  
Author(s):  
Charles A. McKeel
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Small Diameter ◽  
Pressure Vessels ◽  
Element Analysis ◽  
Containment Vessel ◽  
Fea Model ◽  
Significant Difference ◽  
Load Increase ◽  
The Difference

Closure bolt loads in a flanged cylindrical containment vessel under internal pressure are determined by detailed Finite Element Analysis (FEA) and compared to values determined using NUREG/CR-6007 equations. The containment vessel is of small diameter with an inwardly dished bolted head that geometrically contrasts with the large, flat lidded casks which the NUREG addressed. The comparison showed a significant difference in the magnitude of pressure driven prying load between the FEA model and the NUREG approximate equations. This difference affected the predicted pressure that overcomes preload, and the rate of load increase after preload was exceeded. The difference was likely due to the contrasts between this vessel’s closure shape compared to the more typical flat cask lid shape used in the NUREG development.

Hardness prediction of a cold rolled Nimonic 80A exhaust valve spindle

2019 ◽  
Vol 1-2 (94) ◽  
pp. 13-21
Author(s):  
S.W. Kang ◽  
S.J. Heo ◽  
J.H. Yoo ◽  
J.H. Kang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fe Analysis ◽  
Compression Testing ◽  
Hardness Distribution ◽  
Stress Strain ◽  
Element Analysis ◽  
Nimonic 80A ◽  
Strain Relationship ◽  
Cold Rolled

Purpose: of this paper is to predict the hardness of cold rolled exhausts valve spindle fabricated of Nimonic 80A via axisymmetric finite element analysis, compression testing, and hardness inspection. Design/methodology/approach: The stress-strain relationship of Nimonic 80A was obtained via compression testing with deformation ratios of 10%, 20%, and 30%. Hardness changes caused by the strain hardening effect were measured in cut specimens in both the axial and circumferential directions following compression testing. The effective strain at the measurement position was calculated via finite element analysis. The regression equation for hardness changes caused by work hardening was derived from analysed strain and inspected hardness. The cold-rolling deformation of an exhaust valve spindle was analysed using axisymmetric finite element analysis. Findings: The stress-strain relationship calculated from compression testing was well expressed using the Holloman equation and the strain-hardness relationship by strain hardening was successfully regressed using the shifted power law model for Nimonic 80A, Nickel-Chromium based super alloy. Research limitations/implications: This research focused hardness prediction of spindle after ring rolling operation for generating beneficial compressive surface residual stresses for enhancing fatigue life. Further research to quantify compressive residual stress after rolling shall be followed to increase fatigue life. Practical implications: The cold rolling process is a typical incremental forming method and should be analysed under three-dimensional conditions. However, it takes lots of time to solve incremental forming analysis. To predict hardness distribution after rolling in the manufacturing field, FE analysis was performed under two-dimensional axisymmetric conditions based on the assumption of no friction generated by the rolling tool. The deformed shapes and hardness distribution from the inspection quality standard and two-dimensional FE analysis showed very similar results. Simplified finite element analysis method for ring rolling process for local area could be very effective method in the industrial field. Originality/value: The stress-strain relationship and the hardness and strain relationship were derived by compression test and hardness measurement for compressed specimen for Nimonic 80A, Nickel-Chromium based super alloy. And simplified finite element analysis method was suggested to predict deformed shape and hardness distribution of locally cold rolled region and achieved similar result between FE analysis result and Quality standard. Suggested method would be very effective method to engine spindle manufacture to predict hardness of different size of product.

scholarly journals Solid Model Generation for Digitized Organic Bodies via T-Splines

Heritage ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 606-636
Author(s):  
Luigi Barazzetti
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Point Clouds ◽  
Solid Model ◽  
Model Generation ◽  
Element Analysis ◽  
Mesh Resolution ◽  
The Difference ◽  
Preliminary Extraction ◽  
Solid Bodies

This paper presents a workflow for B-rep solid model generation of organic objects using T-splines constructed with quad-meshes. The aim is the creation of geometrically and topologically consistent B-rep solid models of heritage objects featuring organic shapes, which can be used in numerical simulation based on meshless finite element analysis. Point clouds and closed triangular meshes are converted into B-rep solids with a multi-step procedure based on the preliminary extraction of quadrilateral meshes, which are used to produce T-splines. Evaluation of metric quality is carried out to quantify the difference between the final solid and input datasets. A coarse-to-fine approach can also be exploited by varying the quad-mesh resolution to preserve the level of details captured during the digitization process. Finally, meshless finite element analysis can be run with the produced solid bodies. Results for both simulated and real heritage objects are illustrated and discussed.

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