A Nested Finite Element Methodology (NFEM) for Stress Analysis of Electronic Products—Part I: Theory and Formulation

2000 ◽  
Vol 123 (2) ◽  
pp. 141-146 ◽  
Author(s):  
Krishna Darbha ◽  
Abhijit Dasgupta
Keyword(s):  
Finite Element ◽  
Stress Analysis ◽  
Ritz Method ◽  
Element Analysis ◽  
Thermomechanical Stress ◽  
Surface Mount ◽  
Field Displacement ◽  
Analysis Technique ◽  
P Type ◽  
Finite Element Methodology

In this paper, the authors present a stress analysis technique based on a novel nested finite element methodology (NFEM). The NFEM is similar in concept to an earlier proposed multi-domain Rayleigh-Ritz methodology (Ling, S., 1997, “A Multi-Domain Rayleigh-Ritz Method for Thermomechanical Stress Analysis of Surface Mount Interconnects in Electronic Assemblies,” Ph.D. dissertation, Univ., of Maryland), that is based on a nested multi-field displacement assumption. The nested multi-field displacement technique may be viewed as a localized cascading of the p-type refinement in conventional finite element analysis. The concept and formulation of NFEM are presented in this paper while the application of NFEM to analyze the viscoplastic stress-state in two popular surface mount electronic interconnect styles is presented in Part II of this series. To illustrate the concept of NFEM, the formulation and results are provided for a one-dimensional viscoplastic example.

Finite Element Analysis of Drum on the New Type Self-Driven Towing Machine for Cable

2011 ◽  
Vol 55-57 ◽  
pp. 664-669
Author(s):  
Jin Ning Nie ◽  
Hui Wang ◽  
De Feng Xie
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Analysis ◽  
Compressive Stress ◽  
Wire Rope ◽  
Ansys Software ◽  
Element Analysis ◽  
Structure Improvement ◽  
Improvement Measures ◽  
New Type

According to the situation that the dual-friction drums on the new type towing machine lack stress analysis when designed, the safety is difficult to test and verify. The pull of wire rope in various positions was derived and calculated, so both compressive stress and tangent friction force generated by the pull of wire rope were calculated. The result made by ANSYS software demonstrates the safety of the left drum which suffers from larger loads, structure improvement measures are put forward for the drum.

Stress Analysis and Structure Optimization for the Opening Flat Cover of Pressure Vessels

2012 ◽  
Vol 538-541 ◽  
pp. 3253-3258 ◽  
Author(s):  
Jun Jian Xiao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Stress Analysis ◽  
Structure Optimization ◽  
Pressure Vessels ◽  
Secondary Stress ◽  
Element Analysis ◽  
Primary Stress ◽  
Flat Cover

According to the results of finite element analysis (FEA), when the diameter of opening of the flat cover is no more than 0.5D (d≤0.5D), there is obvious stress concentration at the edge of opening, but only existed within the region of 2d. Increasing the thickness of flat covers could not relieve the stress concentration at the edge of opening. It is recommended that reinforcing element being installed within the region of 2d should be used. When the diameter of openings is larger than 0.5D (d>0.5D), conical or round angle transitions could be employed at connecting location, with which the edge stress decreased remarkably. However, the primary stress plus the secondary stress would be valued by 3[σ].

Practical Procedures for Technical and Economic Investigation of Ship Structural Details

1981 ◽  
Vol 18 (01) ◽  
pp. 51-68
Author(s):  
Donald Liu ◽  
Abram Bakker
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Analysis Techniques ◽  
Structural Problems ◽  
Analysis Technique ◽  
The Finite Element Analysis ◽  
Structural Details

Local structural problems in ships are generally the result of stress concentrations in structural details. The intent of this paper is to show that costly repairs and lay-up time of a vessel can often be prevented, if these problem areas are recognized and investigated in the design stages. Such investigations can be performed for minimal labor and computer costs by using finite-element analysis techniques. Practical procedures for analyzing structural details are presented, including discussions of the results and the analysis costs expended. It is shown that the application of the finite-element analysis technique can be economically employed in the investigation of structural details.

Strength-based design of a sunflower stalk cutter machine design using finite element analysis and experimental validation

2021 ◽  
pp. 095440622110597
Author(s):  
Gürkan İrsel
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Analysis ◽  
Strain Gage ◽  
Experimental Validation ◽  
Experimental Studies ◽  
Fatigue Analysis ◽  
Structural Stress ◽  
Element Analysis ◽  
Strength Based

In this study, the total algorithm of the strength-based design of the system for mass production has been developed. The proposed algorithm, which includes numerical, analytical, and experimental studies, was implemented through a case study on the strength-based structural design and fatigue analysis of a tractor-mounted sunflower stalk cutting machine (SSCM). The proposed algorithm consists of a systematic engineering approach, material selection and testing, design of the mass criteria suitability, structural stress analysis, computer-aided engineering (CAE), prototype production, experimental validation studies, fatigue calculation based on an FE model and experimental studies (CAE-based fatigue analysis), and an optimization process aimed at minimum weight. Approximately 85% of the system was designed using standard commercially available cross-section beams and elements using the proposed algorithm. The prototype was produced, and an HBM data acquisition system was used to collect the strain gage output. The prototype produced was successful in terms of functionality. Two- and three-dimensional mixed models were used in the structural analysis solution. The structural stress analysis and experimental results with a strain gage were 94.48% compatible in this study. It was determined using nCode DesignLife software that fatigue damage did not occur in the system using the finite element analysis (FEA) and experimental data. The SSCM design adopted a multi-objective genetic algorithm (MOGA) methodology for optimization with ANSYS. With the optimization solved from 422 iterations, a maximum stress value of 57.65 MPa was determined, and a 97.72 kg material was saved compared to the prototype. This study provides a useful methodology for experimental and advanced CAE techniques, especially for further study on complex stress, strain, and fatigue analysis of new systematic designs desired to have an optimum weight to strength ratio.

Temperature and Stress Analysis of Corn Kernel— Finite Element Analysis

1979 ◽  
Vol 22 (4) ◽  
pp. 0955-0960 ◽  
Author(s):  
Robert J. Gustafson ◽  
David R. Thompson ◽  
Shahab Sokhansanj
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Analysis ◽  
Corn Kernel ◽  
Element Analysis

Electrochemical Corrosion Finite Element Analysis and Burst Pressure Prediction of Externally Corroded Underground Gas Transmission Pipelines

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Ibrahim M. Gadala ◽  
Magd Abdel Wahab ◽  
Akram Alfantazi
Keyword(s):  
Finite Element ◽  
Stress Analysis ◽  
Reaction Kinetics ◽  
Moving Boundary ◽  
Electrochemical Corrosion ◽  
Burst Pressure ◽  
Element Analysis ◽  
Corrosion Defect ◽  
Nonlinear Stress ◽  
Pipeline Wall

An integrative numerical simulation approach for pipeline integrity analysis is presented in this work, combining a corrosion model, which is the main focus of this paper, with a complementary structural nonlinear stress analysis, using the finite element method (FEM). Potential distributions in the trapped water existing beneath pipeline coating disbondments are modeled in conjunction with reaction kinetics on the corroding exposed steel surface using a moving boundary mesh. Temperature dependencies (25 °C and 50 °C) of reaction kinetics do not greatly affect final corrosion defect geometries after 3-yr simulation periods. Conversely, cathodic protection (CP) levels and pH dependencies within the near-neutral pH range (6.7–8.5) strongly govern depth profiles caused by corrosion, reaching a maximum of ∼3 mm into the pipeline wall. A 0.25 V amplification of CP potential combined with a 0.5 mm widening in disbondment opening size reduces defect penetration by almost 30%. Resulting corrosion defect geometries are used for stress examinations and burst pressure evaluations. Furthermore, nonlinear elastic–plastic stress analysis is carried out using shell elements in order to predict the burst pressure of corroded pipes. Corrosion is modeled by reducing the stiffness of a damaged element that has the dimensions of the defect. The predicted burst pressures are in good agreement with those obtained using an experimental-based formula.

Evaluation and Repair of Cracks on Statically Loaded Beams Using Piezoelectric Actuation

2021 ◽  
Vol 11 (1) ◽  
pp. 34-49
Author(s):  
Goutam Roy ◽  
Brajesh Kumar Panigrahi ◽  
Goutam Pohit
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Ritz Method ◽  
Actuation Voltage ◽  
Piezoelectric Actuation ◽  
Cracked Beam ◽  
Element Analysis ◽  
Various Boundary Conditions ◽  
Piezoelectric Patch ◽  
Loading Patterns

In the present work, damage produced by a crack in a statically loaded beam is first evaluated. Subsequently, an attempt is made to repair the effect of the crack by attaching a piezoelectric patch to the beam as an actuator. Static analysis of PZT patched cracked beam along with rotational spring is performed using Ritz method. Subsequently, a finite element analysis is performed by using ABAQUS 6.12 to collate the analytical results. It is shown in the study that when PZT patch is subjected to external electric field, it yields a local reactive moment, which counters the crack effects. An equation is procured in order to compute the required actuation voltage for repairing of cracks. A parametric study is performed for various boundary conditions and loading patterns. It is distinctly noticed that the technique nullifies the discontinuity in slope curve which develops due to a crack.

INDIVIDUALLY COMPUTED FINITE ELEMENT ANALYSIS OF THE NON-STEMMED ANATOMICAL TOTAL HIP PROSTHESIS

2005 ◽  
Vol 09 (01) ◽  
pp. 21-33
Author(s):  
Poon-Ung Chieng ◽  
Ching-I Chen ◽  
Chi-Chang Lin ◽  
Ching-Lin Tsai ◽  
Po-Quang Chen
Keyword(s):  
Finite Element ◽  
Femoral Neck ◽  
Stress Analysis ◽  
Hip Prosthesis ◽  
Element Model ◽  
Main Body ◽  
Total Hip Prosthesis ◽  
Level Of Evidence ◽  
Element Analysis ◽  
Total Hip

Background: Current total hip prosthesis lack an accurate individualized finite element model to assure an accurate fit, and further require amputation of a possibly healthy femoral neck. Methods: This research presents a new methodology for performing an automated three-dimensional finite element meshing for a new type of total hip prosthesis. The stress analysis for this new design, known as Non-stemmed Anatomical Total Hip Prosthesis, is based on the methodology proposed here. The merit of this method is that the automated meshing process can be produced by using ANSYS software alone, without the need for a complicated, self-developed meshing interface program. Results: This new methodology provides a smooth boundary around the contour of the femur and the interface between the femur and the Non-stemmed Anatomical Total Hip Prosthesis, as well as avoiding additional complications. This newly designed prosthesis involves minimal modification of the intact femoral neck alignment after total hip replacement, provided that the femoral neck is still healthy. The main body of this new prosthesis is a conical-shaped mask that tightly embraces the femoral neck. The bottom skirt of this mask contacts the greater and lesser trochanter in such a way that maintains the mask in the desired position using a screw through the axis of the femoral neck. Finite element stress analysis is performed to compare the stress distribution of the intact femur and the femur after implantation of the Non-stemmed Anatomical Total Hip Prosthesis. Conclusions: Hopefully, this new prosthesis will be the method of choice for patients who have healthy femoral necks, but sick femoral heads. Further research can focus on applying this new methodology to other bone structures. Level of Evidence: Therapeutic study, Level IV.

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