Heat Transfer and Thermal Stress Analysis of an Optoelectronic Package

1991 ◽  
Vol 113 (3) ◽  
pp. 258-262 ◽  
Author(s):  
J. G. Stack ◽  
M. S. Acarlar
Keyword(s):  
Heat Transfer ◽  
Thermal Management ◽  
Power Dissipation ◽  
Point Of View ◽  
Optical Data ◽  
Data Link ◽  
Element Analysis ◽  
Thermally Induced ◽  
Temperature Changes ◽  
Induced Stresses

The reliability and life of an Optical Data Link transmitter are inversely related to the temperature of the LED. It is therefore critical to have efficient packaging from the point of view of thermal management. For the ODL® 200H devices, it is also necessary to ensure that all package seals remain hermetic throughout the stringent military temperature range requirements of −65 to +150°C. For these devices, finite element analysis was used to study both the thermal paths due to LED power dissipation and the thermally induced stresses in the hermetic joints due to ambient temperature changes

Investigation of the Lead-On-Chip Package’s Reliability

1998 ◽  
Vol 120 (2) ◽  
pp. 171-174 ◽  
Author(s):  
P.-H. Tsao ◽  
L. C. Chang ◽  
T. C. Chen ◽  
C. Haung ◽  
C. Z. Chen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Flexural Modulus ◽  
Test Chip ◽  
Element Analysis ◽  
Thermally Induced ◽  
Molding Compounds ◽  
Different Types ◽  
Induced Stresses ◽  
On Chip

An assembly test chip (ATC), consisting of varieties of test structures, had been utilized to monitor the package integrity of SOJ lead-on-chip (LOC) packages after various reliability tests. Two different types of epoxy molding compounds, namely biphenyl and EOCN epoxies, were chosen to investigate their effects on package’s reliability. After the reliability tests, silicon chip crack was observed in three test samples due to the existence of a large chip backside chipping (˜120 μm). Qualitative study about this failure mechanism was carried out by a finite element analysis and it was found that, due to the higher flexural modulus and CTE of the biphenyl epoxy, the thermally induced stresses developed in the chip encapsulated by this epoxy during reliability tests were more likely to cause the crack propagation in the silicon chip than those induced by using EOCN type epoxy.

scholarly journals Uncoupled CFD-FEA Methods for the Thermo-Structural Analysis of Turbochargers

2019 ◽  
Vol 4 (4) ◽  
pp. 39
Author(s):  
Piotr Łuczyński ◽  
Matthias Giesen ◽  
Thomas-Sebastian Gier ◽  
Manfred Wirsum
Keyword(s):  
Heat Transfer ◽  
Accurate Determination ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Mechanical Analysis ◽  
Heating Process ◽  
Transfer Coefficients ◽  
Element Analysis ◽  
Thermally Induced ◽  
Heat Transfer Coefficients

In turbocharger design, the accurate determination of thermally induced stresses is of particular importance for life cycle predictions. An accurate, transient, thermal finite element analysis (FEA) of turbocharger components requires transient conjugate heat transfer (CHT) analysis. However, due to the vastly different timescales of the heat transfer mechanisms in fluid and in solid states, unsteady CHT simulations are burdened by high computational costs. Hence, for design iterations, uncoupled CFD and FEA approaches are needed. The quality of the uncoupled thermal analysis depends on the local heat transfer coefficients (HTC) and reference fluid temperatures. In this paper, multiple CFD-FEA methods known from literature are implemented in a numerical model of a turbocharger. In order to describe the heat transfer and thermal boundary layer of the fluid, different definitions of heat transfer coefficients and reference fluid temperatures are investigated with regard to calculation time and accuracy. For the transient simulation of a long heating process, the combination of the CFD-FEA methods with the interpolation FEA approach is examined. Additionally, a structural-mechanical analysis is conducted. The results of the developed methods are evaluated against experimental data and the results of the extensive unsteady CHT numerical method.

Study on Thermal Management for Cooling System of Aero-Piston Engine

2012 ◽  
Vol 516-517 ◽  
pp. 452-456
Author(s):  
Fen Zhu Ji ◽  
Xiao Xu Zhou ◽  
Mi Tian
Keyword(s):  
Heat Transfer ◽  
Thermal Management ◽  
Cooling System ◽  
Cylinder Block ◽  
Cylinder Wall ◽  
Piston Engine ◽  
Element Analysis ◽  
Flight Height ◽  
Calculation Results ◽  
Block Temperature

A model of thermal management for cooling system of aero-piston engine was presented in this study. The models of main parts in this system were also founded. Based on the measured value of temperature and pressure in the cylinder, the heat transfer coefficient between gas-fired and the cylinder wall was calculated by using the empirical formula. A heat transfer boundary condition between fins and cooling air was determined according to various Reynolds number of the air flow. Moreover, the method of finite element analysis was utilized to calculate the temperature of cylinder block. In the specified working condition of some two-stroke piston engine used in the unmanned aerial vehicle (UAV), the calculation and analysis were made to study on the effect of aircrew speed and flight height on the cylinder block temperature, as well as the effect of cylinder block temperature on airscrew speed by the thermal management model. The calculation results show that, as the flight height rises, the cylinder block temperature increases accordingly when engine power and airscrew speeds are kept constant; however, at the same height, the higher the airscrew speed is, the lower cylinder block temperature will be. The cylinder block temperature should be kept stable by regulating the airscrew speed.

Simulation Of Thermal Stresses, Voids And Fracture At The GaAs/Ceramic Interface

1995 ◽  
Vol 409 ◽  
Author(s):  
Nickolaos Strifas ◽  
Aris Christou
Keyword(s):  
Finite Element ◽  
Thermal Management ◽  
Thermal Stresses ◽  
Temperature Cycling ◽  
Analysis Method ◽  
Element Analysis ◽  
Temperature Changes ◽  
Die Attach ◽  
Element Simulation ◽  
Reliable Performance

AbstractStresses induced at the GaAs-Al2O3 interface by large ΔT excursions have been investigated by finite element simulation and have been correlated with experimental results. The effects of power and temperature cycling on crack propagation at the die attach are investigated. The FEA (finite element analysis) method is used to simulate the effect of die attach voids on the peak surface temperature and on the die stresses. These voids in the die attach are identified to be the major cause of die cracking. It was found that stresses developed on the die because of the environmental temperature changes and their dissipation as part of an effective thermal management is necessary to ensure reliable performance.

Thermally induced stresses and rapid temperature changes in teeth

1972 ◽  
Vol 6 (5) ◽  
pp. 305-325 ◽  
Author(s):  
Robert E. Barker ◽  
Robert F. Rafoth ◽  
Robert W. Ward
Keyword(s):  
Thermally Induced ◽  
Temperature Changes ◽  
Rapid Temperature ◽  
Induced Stresses

Investigation of Steady State and Transient Thermal Management in Portable Telecommunication Product – Part 1

2005 ◽  
Vol 2 (1) ◽  
pp. 40-54 ◽  
Author(s):  
Cheang Soon Yee ◽  
K.N. Seetharamu ◽  
G.A. Quadir ◽  
Z.A. Zainal
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Thermal Management ◽  
Three Dimensional ◽  
Cellular Phone ◽  
Simulation Method ◽  
Conduction Path ◽  
Element Analysis ◽  
Fea Simulation ◽  
Transient Thermal

Steady state and transient thermal management in a portable telecommunication product was investigated. The steady state analysis portion will be discussed in details in Part 1. The investigation was conducted using finite element analysis (FEA) simulation on a cellular phone model. The three-dimensional simulation is based on a solid conduction cellular phone model cooled by natural convection and radiation. The FEA simulation method was verified with experimental results. In this paper, simulation study was carried out to examine various thermal solution options to improve on the heat transfer from the package to the surrounding. As conduction is the predominant heat transfer within the cellular phone, the thermal resistance can be reduced by creating a solid conduction path between the heat dissipating packages with the housing wall and improving the housing wall conduction material.

Morphologies of Nonadherent Al2O3 and Matching Substrate Surfaces

1972 ◽  
Vol 30 ◽  
pp. 524-525
Author(s):  
C. S. Giggins ◽  
J. K. Tien ◽  
B. H. Kear ◽  
F. S. Pettit
Keyword(s):  
Electron Microscopy ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
Substrate Surface ◽  
Morphological Features ◽  
Thermally Induced ◽  
Oxide Spallation ◽  
Oxidation Resistant ◽  
Induced Stresses ◽  
Substrate Surfaces

The performance of most oxidation resistant alloys and coatings is markedly improved if the oxide scale strongly adheres to the substrate surface. Consequently, in order to develop alloys and coatings with improved oxidation resistance, it has become necessary to determine the conditions that lead to spallation of oxides from the surfaces of alloys. In what follows, the morphological features of nonadherent Al2O3, and the substrate surfaces from which the Al2O3 has spalled, are presented and related to oxide spallation.The Al2O3, scales were developed by oxidizing Fe-25Cr-4Al (w/o) and Ni-rich Ni3 (Al,Ta) alloys in air at 1200°C. These scales spalled from their substrates upon cooling as a result of thermally induced stresses. The scales and the alloy substrate surfaces were then examined by scanning and replication electron microscopy.The Al2O3, scales from the Fe-Cr-Al contained filamentary protrusions at the oxide-gas interface, Fig. 1(a). In addition, nodules of oxide have been developed such that cavities were formed between the oxide and the substrate, Fig. 1(a).

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