Stress Analyses of Flip TAB Interconnects in Multi-Chip Module Assembly

1991 ◽  
Vol 113 (3) ◽  
pp. 226-232 ◽  
Author(s):  
Ben Nagaraj ◽  
Mali Mahalingam
Keyword(s):  
High Performance ◽  
Heat Dissipation ◽  
Mechanical Load ◽  
Design Guidelines ◽  
Physical Contact ◽  
Thermal Loads ◽  
Force Components ◽  
Effect Of The Support ◽  
Supporting Element ◽  
Generic Design

Flip Tape Automated Bond (FTAB) interconnect is one of the leading candidates for device to substrate interconnection in a high performance Multi-Chip Module (MCM). The TAB interconnect becomes a structural member in the MCM assembly, bearing both “mechanical” and “thermal” loads. Further, to accomplish high thermal performance in the assembly, physical contact to the device may be made under substantial contact pressures. The device may be supported by elastic structures to redistribute the interconnect forces. Finite Element Methods (FEM) are used to analyze the structural behavior of TAB interconnects under (i) the applied mechanical load to the device and (ii) the thermal loads due to the heat dissipation in the device. Variation of the force components on the TAB interconnects and the maximum failure criterion based on the stresses in the interconnects are reported. Effect of the support area and the modulus of the supporting element on the interconnects are discussed. Generic design guidelines are presented for flip TAB interconnect based MCM assembly.

A Model Predictive Framework for Thermal Management of Aircraft

2015 ◽  
Author(s):  
Timothy O. Deppen ◽  
Joel E. Hey ◽  
Andrew G. Alleyne ◽  
Timothy S. Fisher
Keyword(s):  
Thermal Management ◽  
High Performance ◽  
Heat Dissipation ◽  
Electrical Power ◽  
Electrical Equipment ◽  
Thermal Loads ◽  
Case Scenario ◽  
Worst Case ◽  
Order Of Magnitude ◽  
Transient Thermal

The challenge of managing heat dissipation and enforcing operational constraints on temperature within a high-performance tactical aircraft is considered. For these systems, power density of the electrical equipment and the associated thermal loads are quickly outpacing the means of conventional thermal management systems (TMS) to provide on-demand cooling and in order to prevent thermal run away. The next generation of tactical aircraft is projected to include an order of magnitude greater thermal and electrical power magnitudes, and the time scale over which thermal loads will change is expected to shrink. To meet this rapidly evolving challenge, designing a TMS for the “worst case” scenario based on a steady-state thermal analysis will be infeasible. Rather, a holistic systems perspective is needed with new control methodologies that capture and even exploit the transient thermal behavior. To this end, a model predictive control strategy is presented that utilizes preview of upcoming loads and disturbances to prevent violation of temperature constraints. A simulation case study demonstrates that the predictive thermal controller can dramatically reduce constraint violations while reducing the work required by the TMS when compared to a cascaded PI feedback controller.

Flexural design of precast, prestressed ultra-high-performance concrete members

PCI Journal ◽  
2020 ◽  
Vol 65 (6) ◽  
pp. 35-61
Author(s):  
Chungwook Sim ◽  
Maher Tadros ◽  
David Gee ◽  
Micheal Asaad
Keyword(s):  
Prestressed Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Limit State ◽  
Design Guidelines ◽  
Design Tool ◽  
Supplementary Cementitious Materials ◽  
Ultra High Performance Concrete ◽  
Concrete Members ◽  
Cylinder Strength

Ultra-high-performance concrete (UHPC) is a special concrete mixture with outstanding mechanical and durability characteristics. It is a mixture of portland cement, supplementary cementitious materials, sand, and high-strength, high-aspect-ratio microfibers. In this paper, the authors propose flexural design guidelines for precast, prestressed concrete members made with concrete mixtures developed by precasters to meet minimum specific characteristics qualifying it to be called PCI-UHPC. Minimum specified cylinder strength is 10 ksi (69 MPa) at prestress release and 18 ksi (124 MPa) at the time the member is placed in service, typically 28 days. Minimum flexural cracking and tensile strengths of 1.5 and 2 ksi (10 and 14 MPa), respectively, according to ASTM C1609 testing specifications are required. In addition, strain-hardening and ductility requirements are specified. Tensile properties are shown to be more important for structural optimization than cylinder strength. Both building and bridge products are considered because the paper is focused on capacity rather than demand. Both service limit state and strength limit state are covered. When the contribution of fibers to capacity should be included and when they may be ignored is shown. It is further shown that the traditional equivalent rectangular stress block in compression can still be used to produce satisfactory results in prestressed concrete members. A spreadsheet workbook is offered online as a design tool. It is valid for multilayers of concrete of different strengths, rows of reinforcing bars of different grades, and prestressing strands. It produces moment-curvature diagrams and flexural capacity at ultimate strain. A fully worked-out example of a 250 ft (76.2 m) span decked I-beam of optimized shape is given.

scholarly journals Calculating the optimal hematocrit under the constraint of constant cardiac power

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michal Sitina ◽  
Heiko Stark ◽  
Stefan Schuster
Keyword(s):  
Blood Flow ◽  
High Performance ◽  
Animal Species ◽  
Normal Values ◽  
Mechanical Load ◽  
The Body ◽  
Trade Off ◽  
Cardiac Power ◽  
Optimal Value ◽  
Good Agreement

AbstractIn humans and higher animals, a trade-off between sufficiently high erythrocyte concentrations to bind oxygen and sufficiently low blood viscosity to allow rapid blood flow has been achieved during evolution. Optimal hematocrit theory has been successful in predicting hematocrit (HCT) values of about 0.3–0.5, in very good agreement with the normal values observed for humans and many animal species. However, according to those calculations, the optimal value should be independent of the mechanical load of the body. This is in contradiction to the exertional increase in HCT observed in some animals called natural blood dopers and to the illegal practice of blood boosting in high-performance sports. Here, we present a novel calculation to predict the optimal HCT value under the constraint of constant cardiac power and compare it to the optimal value obtained for constant driving pressure. We show that the optimal HCT under constant power ranges from 0.5 to 0.7, in agreement with observed values in natural blood dopers at exertion. We use this result to explain the tendency to better exertional performance at an increased HCT.

Thermal Behaviors of Passively-Cooled Hybrid Fin Heat Sinks for Lightweight and High Performance Thermal Management

2015 ◽  
Author(s):  
Nico Setiawan Effendi ◽  
Kyoung Joon Kim
Keyword(s):  
Thermal Resistance ◽  
Heat Sink ◽  
High Performance ◽  
Heat Dissipation ◽  
Computational Study ◽  
Heat Sinks ◽  
Channel Diameter ◽  
Internal Channel ◽  
Study Results ◽  
Parametric Effects

A computational study is conducted to explore thermal performances of natural convection hybrid fin heat sinks (HF HSs). The proposed HF HSs are a hollow hybrid fin heat sink (HHF HS) and a solid hybrid fin heat sink (SHF HS). Parametric effects such as a fin spacing, an internal channel diameter, a heat dissipation on the performance of HF HSs are investigated by CFD analysis. Study results show that the thermal resistance of the HS increases while the mass-multiplied thermal resistance of the HS decreases associated with the increase of the channel diameter. The results also shows the thermal resistance of the SHF HS is 13% smaller, and the mass-multiplied thermal resistance of the HHF HS is 32% smaller compared with the pin fin heat sink (PF HS). These interesting results are mainly due to integrated effects of the mass-reduction, the surface area enhancement, and the heat pumping via the internal channel. Such better performances of HF HSs show the feasibility of alternatives to the conventional PF HS especially for passive cooling of LED lighting modules.

Boiling Enhanced Lidded Server Packages for Two-Phase Immersion Cooling Using 3D Metal Printing and Metal Injection Molding Technologies

2021 ◽  
Author(s):  
Jimmy Chuang ◽  
Jin Yang ◽  
David Shia ◽  
Y L Li
Keyword(s):  
Injection Molding ◽  
High Performance ◽  
Heat Dissipation ◽  
Thermal Design ◽  
Metal Injection Molding ◽  
Electronic Packages ◽  
Two Phase ◽  
Immersion Cooling ◽  
Metal Printing ◽  
3D Metal Printing

Abstract In order to meet increasing performance demand from high-performance computing (HPC) and edge computing, thermal design power (TDP) of CPU and GPU needs to increase. This creates thermal challenge to corresponding electronic packages with respect to heat dissipation. In order to address this challenge, two-phase immersion cooling is gaining attention as its primary mode of heat of removal is via liquid-to-vapor phase change, which can occur at relatively low and constant temperatures. In this paper, integrated heat spreader (IHS) with boiling enhancement features is proposed. 3D metal printing and metal injection molding (MIM) are the two approaches used to manufacture the new IHS. The resultant IHS with enhancement features are used to build test vehicles (TV) by following standard electronic package assembly process. Experimental results demonstrated that boiling enhanced TVs improved two-phase immersion cooling capability by over 50% as compared to baseline TV without boiling enhanced features.

Convective Cooling of Compact Electronic Devices via Liquid Metals with Low Melting Points

2021 ◽  
Author(s):  
Guilin Liu ◽  
Jing Liu
Keyword(s):  
Heat Transfer ◽  
Melting Point ◽  
Liquid Metal ◽  
High Performance ◽  
Flow Resistance ◽  
Heat Dissipation ◽  
Liquid Metals ◽  
Electronic Devices ◽  
Convective Cooling ◽  
Heat Exchanger Design

Abstract The increasingly high power density of today's electronic devices requires the cooling techniques to produce highly effective heat dissipation performance with as little sacrifice as possible to the system compactness. Among the currently available thermal management schemes, the convective liquid metal cooling provides considerably high performance due to their unique thermal properties. This paper firstly reviews the studies on convective cooling using low-melting-point metals published in the past few decades. A group of equations for the thermophysical properties of In-Ga-Sn eutectic alloy is then documented by rigorous literature examination, following by a section of correlations for the heat transfer and flow resistance calculation to partially facilitate the designing work at the current stage. The urgent need to investigate the heat transfer and flow resistance of forced convection of low-melting-point metals in small/mini-channels, typical in compact electronic devices, is carefully argued. Some special aspects pertaining to the practical application of this cooling technique, including the entrance effect, mixed convection, and compact liquid metal heat exchanger design, are also discussed. Finally, future challenges and prospects are outlined.

Heat dissipation of underlying multilayered graphene layers grown on Cu–Ni alloys for high-performance interconnects

2022 ◽  
pp. 152506
Author(s):  
Min Hee Jeong ◽  
Hokyun Rho ◽  
Mina Park ◽  
Dong Yeong Kim ◽  
Hyunjung Lee ◽  
...  
Keyword(s):  
High Performance ◽  
Heat Dissipation ◽  
Graphene Layers ◽  
Ni Alloys

Mechanical Reliability of Silicon Microstructures

2021 ◽  
Author(s):  
Toshiyuki Tsuchiya
Keyword(s):  
High Performance ◽  
Measurement Data ◽  
Design Guidelines ◽  
Fatigue Properties ◽  
Mechanical Reliability ◽  
Effective Parameters ◽  
Micro Electro Mechanical Systems ◽  
Device Reliability ◽  
Silicon Microstructures ◽  
Silicon Based

Abstract In this article, an overview of the mechanical reliability of silicon microstructures for micro-electro-mechanical systems (MEMS) is given to clarify what we now know and what we still have to know about silicon as a high-performance mechanical material on the microscale. Focusing on the strength and fatigue properties of silicon, attempts to understand the reliability of silicon and to predict the device reliability of silicon-based microstructures are introduced. The effective parameters on the strength and the mechanism of fatigue failure are discussed with examples of measurement data to show the design guidelines for highly reliable silicon microstructures and devices.

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