Thermoplastic Finite Element Analysis of Unfilled Plated-Through Holes During Wave Soldering

2001 ◽  
Vol 124 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Chia-Yu Fu ◽  
David L. McDowell ◽  
I. Charles Ume
Keyword(s):  
Finite Element ◽  
Temperature Change ◽  
Thermal Loading ◽  
Uniform Temperature ◽  
Printed Wiring Board ◽  
Element Analysis ◽  
Soldering Temperature ◽  
Wave Soldering ◽  
Plated Through Hole ◽  
Transient Thermal

Previous related research has not developed a consensus on the issue of how stress analyses of plated-through hole (PTH)/printed wiring board (PWB) structure subject to uniform temperature change can approximate the fully transient case. In this study, these two types of analyses are conducted using McDowell’s thermoplastic model with previously developed numerical implementation by applying a finite element package and an associated user-defined material subroutine. The same wave soldering temperature profile is used. The detailed stress/strain responses of the copper layer, along the heating and cooling of the wave soldering process, are compared at both the PTH corner and barrel portions. The temperature distributions and corresponding deformations of the model are also reported for the fully transient thermal and one-way coupled mechanical analysis. It is concluded that despite the transient thermal loading, the residual stress and strain distributions within the PTH/PWB structure after cooling can be adequately approximated using the more simple analysis which prescribes a uniform temperature and temperature change at each stage of the process.

Finite Element Analysis of a Gasketed Flange Joint Under Combined Internal Pressure and Thermal Transient Loading

2007 ◽  
Author(s):  
Muhammad Abid ◽  
Javed A. Chattha ◽  
Kamran A. Khan
Keyword(s):  
Finite Element Analysis ◽  
Steady State ◽  
Internal Pressure ◽  
Thermal Loading ◽  
Flange Joint ◽  
Element Analysis ◽  
Transient Loading ◽  
Thermal Transient ◽  
Transient Thermal ◽  
Bolted Flange

Performance of a bolted flange joint is characterized mainly by its ‘strength’ and ‘sealing capability’. A number of analytical and experimental studies have been conducted to study these characteristics only under internal pressure loading. In the available published work, thermal behavior of the pipe flange joints is discussed under steady state loading with and without internal pressure and under transient loading condition without internal pressure. The present design codes also do not address the effects of steady state and thermal transient loading on the structural integrity and sealing ability. It is realized that due to the ignorance of any applied transient thermal loading, the optimized performance of the bolted flange joint can not be achieved. In this paper, in order to investigate gasketed joint’s performance i.e. joint strength and sealing capability under combined internal pressure and transient thermal loading, an extensive nonlinear finite element analysis is carried out and its behavior is discussed.

Clamp Load Decay Due to Material Creep of Lightweight-Material Joints Under Cyclic Temperature

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Sayed A. Nassar ◽  
Amir Kazemi
Keyword(s):  
Finite Element ◽  
Temperature Profile ◽  
Thermal Loading ◽  
Substrate Material ◽  
Valuable Insight ◽  
Substrate Thickness ◽  
Element Analysis ◽  
Fea Model ◽  
Cyclic Temperature ◽  
Material Creep

Experimental and finite element techniques are used for investigating the effect of cyclic thermal loading on the clamp load decay in preloaded single-lap bolted joints that are made of multimaterial lightweight alloys. Substrate material combinations include aluminum, magnesium, and steel, with various coupon thicknesses. The range of cyclic temperature profile varies between −20 °C and +150 °C in a computer-controlled environmental chamber for generating the desired cyclic temperature profile and durations. Real time clamp load data are recorded using strain gage-based, high-temperature, load cells. Clamp load decay is investigated for various combinations of joint materials, initial preload level, and substrate thickness. Thermal and material creep finite element analysis (FEA) is performed using temperature-dependent mechanical properties. The FEA model and results provided a valuable insight into the experimental results regarding the vulnerability of some lightweight materials to significant material creep at higher temperatures.

Finite Element Analysis of Transient Thermal Problems of Work Rolls in Hot Rolling Process

1999 ◽  
Author(s):  
James D. Lee ◽  
Majid T. Manzari ◽  
Yin-Lin Shen ◽  
Wenjun Zeng
Keyword(s):  
Finite Element ◽  
Hot Rolling ◽  
Three Dimensional ◽  
Thermal Characteristics ◽  
Rolling Process ◽  
Thermal Problem ◽  
Element Analysis ◽  
Hot Rolling Process ◽  
Transient Thermal ◽  
Work Rolls

Abstract The three-dimensional transient thermal problem of work rolls in the entire hot rolling process has been formulated. It includes the time-varying boundary conditions specified at the roll surface taking the schedule of both rolling and idling cycles into consideration. The corresponding finite element equations are derived and solved by the Runge-Kutta-Verner method. The finite element solutions indicate that the temperature variations in the circumferential direction are overwhelming. Case studies unveil the thermal characteristics of the work rolls in various kinds of mill operations. Numerical results are presented and compared with Guo’s analytical solutions.

Comprehending Occurrence of Premature Failure in Compressor Turbine (CT) Blades for Short-Haul Aircraft Fleet

2019 ◽  
Vol 42 ◽  
pp. 10-23
Author(s):  
Joshua Kimtai Ngoret ◽  
Venkata Parasuram Kommula
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Pressure ◽  
Thermal Stresses ◽  
Geometrical Model ◽  
Mechanical Stresses ◽  
Element Analysis ◽  
Premature Failure ◽  
Structural Stresses ◽  
Transient Thermal

This paper presents results from modeling of Compressor Turbine (CT) blades for short-haul aircraft fleet occasioned by thermo-mechanical stresses in order to comprehend the occurrence of premature failure. A 3D PT6A-114A engine high pressure (HP) CT blade geometrical model was developed in commercial CAD-SolidWorks, then imported to ANSYS 15.0 environment for finite element analysis (FEA). The CT blade was investigated for transient thermal stresses from heat generated by the combustors and static structural stresses from rotational velocities of the engine which account for 80% of inertial field during flight. The results revealed that the blades could have served for another 1.44% of the time they were in service.

Thermal and Mechanical Characterization of Contiguous Wall Systems for Energy Efficient Low Cost Housing

2011 ◽  
Author(s):  
Barzin Mobasher ◽  
Geoffrey Minor ◽  
Mansour Zenouzi ◽  
Salvador L. Jalife
Keyword(s):  
Finite Element ◽  
Structural Model ◽  
Low Cost ◽  
Structural Walls ◽  
Element Analysis ◽  
Fully Integrated ◽  
Alternative Technologies ◽  
Laminate Theory ◽  
Low Cost Housing ◽  
Transient Thermal

The interaction of alternative technologies for low cost housing using a fully integrated finite element thermal and structural model of the system. The such as matrix formulations, or different wall systems can be accomplished using. Multi-layer systems based on composite laminate theory are used as a substitution for both reinforcement and effective thermal barrier of structural walls and roof systems. Textile Reinforced Cement composites (TRCs) as thin sandwich skin elements are considered since they show improved tension capacity and ductility based a well-bonded and well-distributed reinforcement that minimizes the flaw sizes, leading to the increase in overall strength and ductility. A range of innovative materials are used in a transient thermal analysis of the composite wall system. Using both 2-D and 3-D finite element analysis, field data obtained from interior and exterior faces of three model construction systems are simulated for walls and roof members as a function of time. Using the exterior temperature as the imposed boundary condition, the interior temperatures were predicted and compared with the experimentally obtained results. Sensitivity of the model to changes in parameters is studied for various insulating materials.

Finite Element Analysis of Local Inelastic Strain Based on Stress Redistribution Locus

2008 ◽  
Author(s):  
Shunji Kataoka ◽  
Takuya Sato
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Loading ◽  
Failure Modes ◽  
Elevated Temperatures ◽  
Pressure Vessels ◽  
Stress Redistribution ◽  
Strain Diagram ◽  
Element Analysis ◽  
Inelastic Analysis

Creep-fatigue damage is one of the dominant failure modes for pressure vessels and piping used at elevated temperatures. In the design of these components the inelastic behavior should be estimated accurately. An inelastic finite element analysis is sometimes employed to predict the creep behavior. However, this analysis needs complicated procedures and many data that depend on the material. Therefore the design is often based on a simplified inelastic analysis based on the elastic analysis result, as described in current design codes. A new, simplified method, named, Stress Redistribution Locus (SRL) method, was proposed in order to simplify the analysis procedure and obtain reasonable results. This method utilizes a unique estimation curve in a normalized stress-strain diagram which can be drawn regardless of the magnitude of thermal loading and constitutive equations of the materials. However, the mechanism of SRL has not been fully investigated. This paper presents results of the parametric inelastic finite element analyses performed in order to investigate the mechanism of SRL around a structural discontinuity, like a shell-skirt intersection, subjected to combined secondary bending stress and peak stress. This investigation showed that SRL comprises a redistribution of the peak and secondary stress components and that although these two components exhibit independent redistribution behavior, they are related to each other.

An Analysis of Thermo-Mechanical Behavior in a Multilayer Composite Pipe Under Temperature Variation

2010 ◽  
Author(s):  
Wei Yang ◽  
Jyhwen Wang
Keyword(s):  
Finite Element ◽  
Thermal Stress ◽  
Analytical Solution ◽  
Mechanical Behavior ◽  
Temperature Change ◽  
Thermal Stresses ◽  
Element Model ◽  
Functionally Graded ◽  
Element Analysis ◽  
Graded Materials

A generalized analytical solution of mechanical and thermal induced stresses in a multi-layer composite cylinder is presented. Based on the compatibility condition at the interfaces, an explicit solution of mechanical stress due to inner and outer surface pressures and thermal stress due to temperature change is derived. A finite element model is also developed to provide the comparison with the analytical solution. It was found that the analytical solutions are in good agreement with finite element analysis result. The analytical solution shows the non-linear dependency of thermal stress on the diameters, thicknesses and the material properties of the layers. It is also shown that the radial and circumferential thermal stresses depend linearly on the coefficients of thermal expansion of the materials and the temperature change. As demonstrated, this solution can also be applied to analyze the thermo-mechanical behavior of pipes coated with functionally graded materials.

Thermoelastic Stresses in an Axisymmetric Thick-Walled Tube Under an Arbitrary Internal Transient

2004 ◽  
Vol 126 (3) ◽  
pp. 327-332 ◽  
Author(s):  
A. E. Segall
Keyword(s):  
Thermal Loading ◽  
Series Representation ◽  
Thermoelastic Stress ◽  
Internal Surface ◽  
Stress Fields ◽  
Element Analysis ◽  
Axisymmetric Solution ◽  
Thermoelastic Stresses ◽  
Stress States ◽  
Transient Thermal

A closed-form axisymmetric solution was derived for the transient thermal-stress fields developed in thick-walled tubes subjected to an arbitrary thermal loading on the internal surface with convection to the surrounding external environment. Generalization of the temperature excitation was achieved by using a versatile polynomial composed of integral-and half-order terms. In order to avoid the difficult and potentially error prone evaluation of functions with complex arguments, Laplace transformation and a ten-term Gaver-Stehfest inversion formula were used to solve the resulting Volterra integral equation. The ensuing series representation of the temperature distribution as a function of time and radial position was then used to derive new relationships for the transient thermoelastic stress-states. Excellent agreement was seen between the derived temperature and stress relationships, existing series solutions, and a finite-element analysis when the thermophysical and thermoelastic properties were assumed to be independent of temperature. The use of a smoothed polynomial in the derived relationships allows the incorporation of empirical data not easily represented by standard functions. This in turn permits an easy analysis of the significance of the exponential boundary condition and convective coefficient in determining the magnitudes and distribution of the resulting stress states over time. Moreover, the resulting relationships are easily programmed and can be used to verify and calibrate numerical calculations.

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