scholarly journals Stress Field Gradient Analysis Technique Using Lower-OrderC0Elements

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Jianwei Xing ◽  
Gangtie Zheng
Keyword(s):  
Stress Field ◽  
Lower Order ◽  
Gradient Analysis ◽  
Stress Gradient ◽  
Mathematical Technique ◽  
Element Analysis ◽  
Analysis Technique ◽  
Penrose Pseudoinverse ◽  
Element Type ◽  
Inconsistent Equation

For evaluating the stress gradient, a mathematical technique based on the stress field of lower-orderC0elements is developed in this paper. With nodal stress results and location information, an overdetermined and inconsistent equation of stress gradient is established and the minimum norm least squares solution is obtained by the Moore-Penrose pseudoinverse. This technique can be applied to any element type in comparison with the superconvergent patch (SCP) recovery for the stress gradient, which requires the quadratic elements at least and has to invert the Jacobi and Hessian matrices. The accuracy and validity of the presented method are demonstrated by two examples, especially its merit of achieving high accuracy with lower-order linearC0elements. This method can be conveniently introduced into the general finite element analysis programs as a postprocessing module.

Effect of Refractory᾽s Thermal Expansion Coefficient on the Stress Field of the Top of Gasifier

2011 ◽  
Vol 418-420 ◽  
pp. 997-1001
Author(s):  
Wen Dong Xue ◽  
Xiao Xiao Huang ◽  
Jing Xie ◽  
Gang Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Expansion ◽  
Temperature Field ◽  
Stress Field ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Coefficient Of Thermal Expansion ◽  
Element Analysis ◽  
Analysis Technique

The top of COREX-C3000 gasifier was simulated with a finite element analysis technique. It is studied of the influence of thermal expansion coefficient of the refractories on the temperature field and stress field and the function discipline with different parameters. The results of the simulation indicated that when the coefficient of thermal expansion of working lining and permanent lining are respectively 3.5×10-6/K and 4.5×10-6/K, the distortion and initial stress of the gasifier top are much less.

3D Coupled Thermomechanical Finite Element Analysis of Ultrasonic Consolidation

2007 ◽  
Vol 539-543 ◽  
pp. 2651-2656 ◽  
Author(s):  
C.J. Huang ◽  
E. Ghassemieh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Friction Coefficient ◽  
Stress Field ◽  
Ultrasonic Wave ◽  
Ultrasonic Vibration ◽  
Softening Effect ◽  
Element Analysis ◽  
Consolidation Process ◽  
Ultrasonic Consolidation

A 3-D coupled temperature-displacement finite element analysis is performed to study an ultrasonic consolidation process. Results show that ultrasonic wave is effective in causing deformation in aluminum foils. Ultrasonic vibration leads to an oscillating stress field. The oscillation of stress in substrate lags behind the ultrasonic vibration by about 0.1 cycle of ultrasonic wave. The upper foil, which is in contact with the substrate, has the most severe deformation. The substrate undergoes little deformation. Apparent material softening by ultrasonic wave, which is of great concern for decades, is successfully simulated. The higher the friction coefficient, the more obvious the apparent material softening effect.

Application of Earthquake Resistance Analysis Technique in the Design of Constructional Engineering

2013 ◽  
Vol 756-759 ◽  
pp. 4482-4486
Author(s):  
Chun Gan ◽  
Xue Song Luo
Keyword(s):  
Response Spectrum ◽  
Structural Response ◽  
Time History ◽  
Economic Losses ◽  
Element Analysis ◽  
Architectural Engineering ◽  
Analysis Technique ◽  
History Analysis ◽  
Earthquake Resistant ◽  
History Of

In recent years, frequent earthquakes have caused great casualties and economic losses in China. And in the earthquake, damage of buildings and the collapse is the main reason causing casualties. Therefore, in the design of constructional engineering, a seismicity of architectural structure is the pressing task at issue. Through time history analysis method, this paper analyzes the time history of building structural response and then it predicts the peak response of mode by response spectrum analysis. Based on this, this paper constructs a numerical simulation model for the architecture by using finite element analysis software SATWE. At the same time, this paper also calculates the structure seismic so as to determine the design of each function structure in architectural engineering design and then provides reference for the realization of earthquake-resistant building.

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.

Finite Element Analysis of a Simply Supported MR Fluid Sandwich Beam Based on ANSYS

2011 ◽  
Vol 94-96 ◽  
pp. 902-908 ◽  
Author(s):  
Zheng Xin Zhang ◽  
Fang Lin Huang ◽  
Yan Bin Wu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shear Modulus ◽  
Sandwich Beam ◽  
Main Idea ◽  
Magnetorheological Fluid ◽  
Element Analysis ◽  
Simply Supported ◽  
Mr Dampers ◽  
Element Type

This paper presents a method to simulate the mechanical behavior of magnetorheological fluid (MRF) subjected to magnetic field in the pre-yield region in ANSYS. The main idea is to devide an MRF element into two coincident elements, one of them has density and viscosity without shear modulus while another has shear modulus without density and viscosity. Taking a simply supported MRF sandwich beam as an example, good results and reasonable conclusion are obtained by comparing the results with the theoretical analysis and experimental study of Ref.[1]. The validity of finite element analysis is also investigated in this paper. At present, there is no exactly appropriate element type in ANSYS to model MRF, this kind of method called coincident elements method (CEM) will provide a new way to model the structures with MRF or MR dampers in ANSYS, and it also has reference roles for the future development of related elements in ANSYS.

Thin Thermally Efficient ICECool Defense Semiconductor Power Amplifiers

2017 ◽  
Vol 14 (3) ◽  
pp. 77-93 ◽  
Author(s):  
Sumeer Khanna ◽  
Patrick McCluskey ◽  
Avram Bar-Cohen ◽  
Bao Yang ◽  
Michael Ohadi
Keyword(s):  
Heat Flux ◽  
Structural Reliability ◽  
Mechanical Design ◽  
Substrate Thickness ◽  
Time To Failure ◽  
Failure Model ◽  
High Concentration ◽  
Element Analysis ◽  
Analysis Technique ◽  
Compact Design

Abstract Traditional power electronics for military and fast computing applications are bulky and heavy. The “mechanical design” of electronic structure and “materials” of construction of the components have limitations in performance under very high temperature conditions. The major concern here is “thermal management.” To be more specific, this refers to removal of high-concentration hotspot heat flux >5 kW/cm2, background heat flux >1 kW/cm2, and “miniaturization” of device within a substrate thickness of <100 μm. We report on the novel applications of contact-based thermoelectric cooling (TEC) to successful implementations of high-conductivity materials - diamond substrate grown on gallium nitride (GaN)/AlGaN transistors to keep the hotspot temperature rise of device below 5 K. The requirement for smarter and faster functionality along with a compact design is considered here. These efforts have focused on the removal of higher levels of heat flux, heat transfer across interface of junction and substrate, advanced packaging and manufacturing concepts, and integration of TEC of GaN devices to nanoscale. The “structural reliability” is a concern and we have reported the same in terms of mean time to failure (cycles) of SAC305 (96.5% tin, 3% silver, 0.5% cu) solder joint by application of Engelmaier's failure model and evaluation of stresses in the structure. The mathematical equation of failure model incorporates the failure phenomena of fatigue and creep in addition to the dwell time, average solder temperature, and plastic strain accumulation. The approach to this problem is a nonlinear finite element analysis technique, which incorporates thermal, mechanical, and thermoelectric boundary conditions.

Thermal Simulation of an Arbitrary Residual Stress Field in a Fully or Partially Autofrettaged Thick-Walled Spherical Pressure Vessel

2008 ◽  
Author(s):  
M. Perl
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Field ◽  
Pressure Vessel ◽  
Stress Fields ◽  
Equivalent Temperature ◽  
Residual Stress Field ◽  
Element Analysis ◽  
Spherical Pressure ◽  
The Ideal

The equivalent thermal load was previously shown to be the only feasible method by which the residual stresses due to autofrettage and its redistribution, as a result of cracking, can be implemented in a finite element analysis, of a fully or partially autofrettaged thick-walled cylindrical pressure vessel. The present analysis involves developing a similar methodology for treating an autofrettaged thick-walled spherical pressure vessel. A general procedure for evaluating the equivalent temperature loading for simulating an arbitrary, analytical or numerical, spherosymmetric autofrettage residual stress field in a spherical pressure vessel is developed. Once presented, the algorithm is applied to two distinct cases. In the first case, an analytical expression for the equivalent thermal loading is obtained for the ideal autofrettage stress field in a spherical shell. In the second case, the algorithm is applied to the discrete numerical values of a realistic autofrettage residual stress field incorporating the Bauschinger effect. As a result, a discrete equivalent temperature field is obtained. Furthermore, a finite element analysis is performed for each of the above cases, applying the respective temperature field to the spherical vessel. The induced stress fields are evaluated for each case and then compared to the original stress. The finite element results prove that the proposed procedure yields equivalent temperature fields that in turn simulate very accurately the residual stress fields for both the ideal and the realistic autofrettage cases.

Modeling and Simulation of High Speed Intermittent Cutting Based on the Finite Element Method

2013 ◽  
Vol 683 ◽  
pp. 556-559
Author(s):  
Bin Bin Jiao ◽  
Fu Sheng Yu ◽  
Yun Jiang Li ◽  
Rong Lu Zhang ◽  
Gui Lin Du ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Field ◽  
Cutting Force ◽  
High Speed ◽  
Element Model ◽  
Periodic Variation ◽  
Element Analysis ◽  
Intermittent Cutting ◽  
Element Method

In order to study the distribution of the stress field in the high-speed intermittent cutting process, finite element model of high-speed intermittent cutting is established. Exponential material model of the constitutive equation and adaptive grid technology are applied in the finite element analysis software AdvantEdge. The material processing is simulated under certain cutting conditions with FEM ( Finite Element Method ) and the distribution of cutting force, stress field, and temperature field are received. A periodic variation to the cutting force and temperature is showed in the simulation of high-speed intermittent cutting. Highest value of the milling temperature appears in front contacting area of the knife -the chip.and maximum stress occurs at the tip of tool or the vicinity of the main cutting edge. The analysis of stress and strain fields in-depth is of great significance to improve tool design and durability of tool.

Development of a Design Sensitivity Analysis Technique for Explicit Finite Element Software With Applications in Crashworthiness

2000 ◽  
Author(s):  
Douglas W. Stillman
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Time Integration ◽  
Design Sensitivity ◽  
Design Sensitivity Analysis ◽  
Element Analysis ◽  
Automotive Safety ◽  
Explicit Finite Element ◽  
Finite Element Software ◽  
Analysis Technique

Abstract Design Sensitivity Analysis (DSA) is a widely used technique in many areas of finite element analysis, but one that hasn’t yet become available for industrial problems in crashworthiness and automotive safety. In the following effort, an implementation of DSA in the automotive safety simulation program, Radioss, is described. Radioss is a non-linear structures program using an explicit time integration method. A full set of DSA equations are developed and integrated into Radioss so that the design sensitivities can be computed directly and accurately as a result of a single crashworthiness simulation. Some validation results are included. The resulting methodology promises to be an extremely useful tool for engineers involved in the design of safety and crashworthiness of automobiles.

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