A Note on the Implementation of Temperature Dependent Coefficient of Thermal Expansion (CTE) in ABAQUS

1992 ◽  
Vol 114 (4) ◽  
pp. 470-472 ◽  
Author(s):  
Yi-Hsin Pao ◽  
Edward Jih ◽  
Bruce E. Artz ◽  
Larry W. Cathey
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Quantitative Measure ◽  
Element Model ◽  
Electronic Packages ◽  
Not Given ◽  
Temperature Dependent ◽  
The Finite Element Model ◽  
Implementation Steps

When modeling the thermomechanical behavior of electronic packages, engineers often need to include the temperature dependence of coefficients of thermal expansion (CTE) of materials involved in the finite element model. In ABAQUS some input parameters associated with such temperature dependent CTE are not clearly defined, and directions to determine the value of these parameters are not given. Misinterpretation of these variables can result in serious errors in the finite element result. This brief tends to illustrate in detail the implementation steps of the temperature dependent CTE in ABAQUS and presents an error analysis so that a quantitative measure of the error can be obtained. The information presented here is regarded critical to those who are using ABAQUS with temperature dependent CTE.

Extraction of the Coefficient of Thermal Expansion of Thin Films from Buckled Membranes

1998 ◽  
Vol 546 ◽  
Author(s):  
V. Ziebartl ◽  
O. Paul ◽  
H. Baltes
Keyword(s):  
Thin Films ◽  
Finite Element ◽  
Thermal Expansion ◽  
Silicon Nitride ◽  
Excellent Agreement ◽  
Energy Minimization ◽  
Coefficient Of Thermal Expansion ◽  
Temperature Dependent ◽  
Minimization Method ◽  
Energy Minimization Method

AbstractWe report a new method to measure the temperature-dependent coefficient of thermal expansion α(T) of thin films. The method exploits the temperature dependent buckling of clamped square plates. This buckling was investigated numerically using an energy minimization method and finite element simulations. Both approaches show excellent agreement even far away from simple critical buckling. The numerical results were used to extract Cα(T) = α0+α1(T−T0 ) of PECVD silicon nitride between 20° and 140°C with α0 = (1.803±0.006)×10−6°C−1, α1 = (7.5±0.5)×10−9 °C−2, and T0 = 25°C.

A Real-Time Neural Network Estimator for Workpiece Thermal Expansion Errors

2000 ◽  
Author(s):  
A. D. Yoder ◽  
R. N. Smith
Keyword(s):  
Neural Network ◽  
Finite Element ◽  
Thermal Expansion ◽  
Finite Element Model ◽  
Real Time ◽  
Element Model ◽  
Precision Machining ◽  
Machining Processes ◽  
The Neural Network ◽  
The Finite Element Model

Abstract The importance of predicting and reducing thermal expansion errors in workpieces is becoming greater as better precision machining processes are developed. An artificial neural network model to estimate the workpiece thermal expansion errors in real-time during precision machining operations is developed and compared with experimental results. A finite element model of workpiece thermal expansion has been created to predict expansions in a thin cylinder undergoing a turning process. The neural network has been trained using finite element model solutions over a range of conditions to allow for changing machining parameters. To realize “on-line” capability, the measurable values of heat flux into the workpiece, surface heat transfer coefficient, and tool location are used as inputs and the expansion as the output for the neural network. The estimations of the network are compared with experimental results from a turning process on a large diameter aluminum cylinder. There is reasonable agreement between measured and estimated expansions with an average error of 18%. The neural network has not been trained at the cutting conditions used during the experiment. The speed of the neural network estimation is much greater than the solution to the finite element model. The finite element model required over 15 minutes to solve on a Pentium 133Mhz computer. The neural network calculated the expansions easily at 1 Hz during the experiment on the same computer. With real-time estimation using measurable data, compensation can be made in the tool path to correct for these errors. The application of this method to precision machining processes has the capability of greatly reducing the error caused by workpiece thermal expansions.

Finite element simulation and experimental investigation on the effect of temperature on pseudoelastic behavior of perforated Ni–Ti shape memory alloy strips

2021 ◽  
Author(s):  
Emre Altas ◽  
Farshid Khosravi Maleki ◽  
Hasan Gokkaya ◽  
Vahid Arab Maleki ◽  
Yüksel Akınay ◽  
...  
Keyword(s):  
Finite Element ◽  
Shape Memory ◽  
Element Model ◽  
Effect Of Temperature ◽  
Flexural Stiffness ◽  
Temperature Dependent ◽  
Three Point Bending ◽  
Increasing Temperature ◽  
The Finite Element Model ◽  
Pseudoelastic Behavior

Abstract In the present study, the temperature-dependent pseudoelastic behavior of shape memory alloy sheets is studied experimentally and by finite element modeling. For this purpose, temperature-dependent mechanical properties for Ni-Ti alloy materials are first obtained by using direct tensile and three-point bending experiments at 23, 50, and 80 °C temperatures, respectively. The structure of these materials is examined at different temperatures using SEM images and the XRD test. Furthermore, using the finite element model, the pseudoelastic behavior and the effect of temperature on the residual deflection of the prose-shape memory strips with a circular hole under three-point bending loads are studied. After validating the results of the finite element model with the results of experimental tests, the effects of various parameters such as the diameter and number of holes on residual deformation and residual strains are investigated. The results show that with increasing temperature, the mechanical properties including the tensile strength, Young's modulus, yield stress, and flexural strength of SMA strips increase significantly. For solid strips, although increasing the temperature increases the maximum flexural force, in contrast, it reduces the flexural stiffness. In solid strips, flexural stiffness decreases by 5.5% with increasing temperature from 23 °C to 80 °C.

Design of a Composite Encapsulation for Concentrated Photovoltaic Systems With Improved Performance

2019 ◽  
Author(s):  
Kabeer Raza ◽  
Syed Sohail Akhtar ◽  
Abul Fazal M. Arif ◽  
Abbas Saeed Hakeem
Keyword(s):  
Thermal Conductivity ◽  
Finite Element ◽  
Thermal Expansion ◽  
Shear Modulus ◽  
Material Properties ◽  
Coefficient Of Thermal Expansion ◽  
Material Design ◽  
Element Model ◽  
Parametric Studies

Abstract Most of the currently used encapsulants are inefficient for cooled concentrated photovoltaic (CPV) systems. The encapsulant of cells for CPV systems, must have an optimum combination of thermal conductivity, coefficient of thermal expansion and long term shear modulus. In this work an improved backside composite encapsulation is designed and developed that can provide increased power output and longer life by enhancing the effectiveness of cooling and reducing thermal stresses. The best combination of material properties is identified through parametric studies on finite element model of CPV laminate using ethylene vinyl acetate as datum line. It is found that increasing thermal conductivity from 0.311 to 0.75 W/mK can improve the cooling and hence the power production by 2%. While long term shear modulus and coefficient of thermal expansion needs to be reduced for a longer service life. Using in-house built material design codes, optimum combinations of matrix and filler were identified that could provide the set range of properties. In line with material design code, a total of only four samples using thermoplastic polyurethane as matrix and Al2O3 or AlN as fillers were synthesized to validate the design experimentally. The material properties were measured and used in the parent finite element model to evaluate the performance of the experimentally developed material and to validate the parametric studies. A good agreement is found between the experimental and computational results and hence the overall methodology is found effective for application focused design and development of composite materials. It is expected that this material design and development approach will provide a useful guideline to the CPV manufacturing industries.

Stress Analysis of the Pressurized-Water Reactor Control Rod Under Operating Conditions

2020 ◽  
Author(s):  
Leo A. Carrilho
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Finite Element Model ◽  
Stress Analysis ◽  
Maximum Stress ◽  
Element Model ◽  
Operating Conditions ◽  
Pressurized Water ◽  
Control Rod ◽  
The Finite Element Model

Abstract This work aims to develop a finite element model of a PWR control rod at operating conditions for stress analysis of the rod cladding. The finite element model simulates a control rod exposed to high operating temperatures and pressure while portions of the rod are irradiated, resulting in accumulated fluence of neutrons by the rod materials. These high temperature and accumulated fluence induce thermal expansion and swelling of the rod materials, especially of the absorber, which may eventually interact with the rod cladding, generating stresses and strains in the wall of the cladding tube. Moreover, if the maximum stress or strain in the tube wall exceeds the design allowable limit, the absorber rod is considered failed. The author creates the control rod finite element model and apply the operating loads on two-dimensional axisymmetric elements to obtain displacements, temperatures, stresses, and strains. The model also includes contact surface elements to evaluate eventual mechanical interactions between absorber and cladding due to thermal expansion and swelling effects. This is a coupled nonlinear static analysis solution that includes thermal expansion effects to calculate temperature distribution and subsequent thermal strains in the absorber rod due to the heat generation rates and coolant temperature; swelling analysis to calculate absorber growth induced by irradiation; and creep analysis to calculate absorber stress relaxation under coolant pressure and temperature. The finite element model is capable of determining whether or not absorber-to-cladding gap closure will occur and if so, calculate maximum stress and strain in the rod cladding associated with mechanical interaction between the two components induced by the operating temperature and thermal fluence loads.

Study on the Thermal Expansion Displacement during Spot Welding Depending on the Multi-Physical Coupling Finite Element Model

2014 ◽  
Vol 941-944 ◽  
pp. 2007-2011
Author(s):  
Cai Ping Liang ◽  
Yong Bing Li
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Finite Element Model ◽  
Spot Welding ◽  
Welding Process ◽  
Physical And Mechanical Properties ◽  
Element Model ◽  
Temperature Dependent ◽  
Monitoring And Forecasting

An incremental and thermal electro-mechanical coupled finite element model has been presented in this study for predicting spot nugget size, gap between workpieces, and thermal expansion displacement during spot welding process. Approximate temperature dependent material properties, including physical and mechanical properties, have been considered. The spot nugget shape and the thermal expansion displacement were obtained by simulation. The solutions showed that the displacement of workpieces was directly related to the quality of solder joints and can be as a monitoring parameter of spot weld quality. These calculations provide a theoretical reference for nugget quality monitoring and forecasting by electrode expansion displacements.

Redrawing Operation a Star Shape from Cylindrical Shape Using Experimental and FE Analysis

2020 ◽  
Vol 38 (1A) ◽  
pp. 25-32
Author(s):  
Waleed Kh. Jawad ◽  
Ali T. Ikal
Keyword(s):  
Finite Element ◽  
Effective Strain ◽  
Element Model ◽  
Cylindrical Shape ◽  
Element Analysis ◽  
Punch Force ◽  
Maximum Value ◽  
Element Simulation ◽  
Blank Sheet ◽  
The Finite Element Model

The aim of this paper is to design and fabricate a star die and a cylindrical die to produce a star shape by redrawing the cylindrical shape and comparing it to the conventional method of producing a star cup drawn from the circular blank sheet using experimental (EXP) and finite element simulation (FES). The redrawing and drawing process was done to produce a star cup with the dimension of (41.5 × 34.69mm), and (30 mm). The finite element model is performed via mechanical APDL ANSYS18.0 to modulate the redrawing and drawing operation. The results of finite element analysis were compared with the experimental results and it is found that the maximum punch force (39.12KN) recorded with the production of a star shape drawn from the circular blank sheet when comparing the punch force (32.33 KN) recorded when redrawing the cylindrical shape into a star shape. This is due to the exposure of the cup produced drawn from the blank to the highest tensile stress. The highest value of the effective stress (709MPa) and effective strain (0.751) recorded with the star shape drawn from a circular blank sheet. The maximum value of lamination (8.707%) is recorded at the cup curling (the concave area) with the first method compared to the maximum value of lamination (5.822%) recorded at the cup curling (the concave area) with the second method because of this exposure to the highest concentration of stresses. The best distribution of thickness, strains, and stresses when producing a star shape by

Analysis of Hydroelectric Unit’s Upper Bracket Based on Test and FEM

2014 ◽  
Vol 721 ◽  
pp. 131-134
Author(s):  
Mi Mi Xia ◽  
Yong Gang Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Element Model ◽  
The Finite Element Method ◽  
Ansys Software ◽  
Element Analysis ◽  
Hydroelectric Unit ◽  
The Finite Element Analysis ◽  
Strain Rosette ◽  
The Finite Element Model

To research the load upper bracket of Francis hydroelectric unit, then established the finite-element model, and analyzed the structure stress of 7 operating condition points with the ANSYS software. By the strain rosette test, acquired the data of stress-strain in the area of stress concentration of the upper bracket. The inaccuracy was considered below 5% by analyzing the contradistinction between the finite-element analysis and the test, and match the engineering precision and the test was reliable. The finite-element method could be used to judge the stress of the upper bracket, and it could provide reference for the Structural optimization and improvement too.

Analysis of Premium Connection of Connecting and Sealing Ability Loaded by Axial Tensile Loads

2012 ◽  
Vol 268-270 ◽  
pp. 737-740
Author(s):  
Yang Yu ◽  
Yi Hua Dou ◽  
Fu Xiang Zhang ◽  
Xiang Tong Yang
Keyword(s):  
Finite Element ◽  
Contact Pressure ◽  
Tensile Load ◽  
Element Model ◽  
Sealing Ability ◽  
Axial Tensile ◽  
High Level ◽  
Maximum Contact ◽  
Contact Pressures ◽  
The Finite Element Model

It is necessary to know the connecting and sealing ability of premium connection for appropriate choices of different working conditions. By finite element method, the finite element model of premium connection is established and the stresses of seal section, shoulder zone and thread surface of tubing by axial tensile loads are analyzed. The results show that shoulder zone is subject to most axial stresses at made-up state, which will make distribution of stresses on thread reasonable. With the increase of axial tensile loads, stresses of thread on both ends increase and on seal section and shoulder zone slightly change. The maximum stress on some thread exceed the yield limit of material when axial tensile loads exceed 400KN. Limited axial tensile loads sharply influence the contact pressures on shoulder zone while slightly on seal section. Although the maximum contact pressure on shoulder zone drop to 0 when the axial tensile load is 600KN, the maximum contact pressure on seal section will keep on a high level.

The structural optimization of roadheader conical picks based on fatigue life

2018 ◽  
Vol 09 (02) ◽  
pp. 1850013 ◽  
Author(s):  
Zhenguo Lu ◽  
Lirong Wan ◽  
Qingliang Zeng ◽  
Xin Zhang ◽  
Kuidong Gao
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Static Analysis ◽  
Element Model ◽  
Cutting Resistance ◽  
Strength Failure ◽  
New Type ◽  
Conical Picks ◽  
Fatigue Life Analysis ◽  
The Finite Element Model

Conical picks are the key cutting components used on roadheaders, and they are replaced frequently because of the bad working conditions. Picks did not meet the fatigue life when they were damaged by abrasion, so the pick fatigue life and strength are excessive. In the paper, in order to reduce the abrasion and save the materials, structure optimization was carried out. For static analysis and fatigue life prediction, the simulation program was proposed based on mathematical models to obtain the cutting resistance. Furthermore, the finite element models for static analysis and fatigue life analysis were proposed. The results indicated that fatigue life damage and strength failure of the cutting pick would never happen. Subsequently, the initial optimization model and the finite element model of picks were developed. According to the optimized results, a new type of pick was developed based on the working and installing conditions of the traditional pick. Finally, the previous analysis methods used for traditional methods were carried out again for the new type picks. The results show that new type of pick can satisfy the strength and fatigue life requirements.

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