A Systematic Approach for Designing Multifunctional Thermally Conducting Polymer Structures With Embedded Actuators

2009 ◽  
Vol 131 (11) ◽  
Author(s):  
Wojciech Bejgerowski ◽  
Satyandra K. Gupta ◽  
Hugh A. Bruck

Thermally conductive filled polymers enable the creation of multifunctional structures that offer both anchoring points for the embedded actuators, as well as heat-dissipation functions, in order to facilitate the miniaturization of devices. However, there are two important challenges in creating these structures: (1) sufficient thermal management to prevent failure of the actuator and (2) the ability of the actuator to survive the manufacturing process. This paper describes a systematic approach for design of multifunctional structures with embedded heat-generating components using an in-mold assembly process to address these challenges. For the first challenge, the development of appropriate thermal models is presented along with incorporation of in-mold assembly process constraints in the optimization process. For the second challenge, a simulation of the molding process is presented and demonstrated to enable the determination of processing conditions ensuring survival of the in-mold assembly process for the embedded actuator. Thus, the design methodology described in this paper was utilized to concurrently optimize the choice of material, size of the structure, and processing conditions in order to demonstrate the feasibility of creating multifunctional structures from thermally conductive polymers by embedding actuators through an in-mold assembly process.

2017 ◽  
Vol 1 (10) ◽  
pp. 2145-2154 ◽  
Author(s):  
Bo Zhao ◽  
Xian-Zhu Fu ◽  
Rong Sun ◽  
Ching-Ping Wong

The highly thermally conductive graphene-based electrodes for supercapacitors exhibit great heat dissipation ability as well as excellent cycling performance and rate capacity.


1974 ◽  
Vol 41 (3) ◽  
pp. 647-651 ◽  
Author(s):  
Myron Levitsky ◽  
Bernard W. Shaffer

A method has been formulated for the determination of thermal stresses in materials which harden in the presence of an exothermic chemical reaction. Hardening is described by the transformation of the material from an inviscid liquid-like state into an elastic solid, where intermediate states consist of a mixture of the two, in a ratio which is determined by the degree of chemical reaction. The method is illustrated in terms of an infinite slab cast between two rigid mold surfaces. It is found that the stress component normal to the slab surfaces vanishes in the residual state, so that removal of the slab from the mold leaves the remaining residual stress unchanged. On the other hand, the residual stress component parallel to the slab surfaces does not vanish. Its distribution is described as a function of the parameters of the hardening process.


Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2286
Author(s):  
Jan Kominek ◽  
Martin Zachar ◽  
Michal Guzej ◽  
Erik Bartuli ◽  
Petr Kotrbacek

Miniaturization of electronic devices leads to new heat dissipation challenges and traditional cooling methods need to be replaced by new better ones. Polymer heat sinks may, thanks to their unique properties, replace standardly used heat sink materials in certain applications, especially in applications with high ambient temperature. Polymers natively dispose of high surface emissivity in comparison with glossy metals. This high emissivity allows a larger amount of heat to be dissipated to the ambient with the fourth power of its absolute surface temperature. This paper shows the change in radiative and convective heat transfer from polymer heat sinks used in different ambient temperatures. Furthermore, the observed polymer heat sinks have differently oriented graphite filler caused by their molding process differences, therefore their thermal conductivity anisotropies and overall cooling efficiencies also differ. Furthermore, it is also shown that a high radiative heat transfer leads to minimizing these cooling efficiency differences between these polymer heat sinks of the same geometry. The measurements were conducted at HEATLAB, Brno University of Technology.


Author(s):  
Tatiana Pogarskaia ◽  
Sergey Lupuleac ◽  
Julia Shinder ◽  
Philipp Westphal

Abstract Riveting and bolting are common assembly methods in aircraft production. The fasteners are installed immediately after hole drilling and fix the relative tangential displacements of the parts, that took place. A proper fastener sequence installation is very important because a wrong one can lead to a “bubble-effect”, when gap between parts after fastening becomes larger in some areas rather than being reduced. This circumstance affects the quality of the final assembly. For that reason, the efficient methods for determination of fastening sequence taking into account the specifics of the assembly process are needed. The problem is complicated by several aspects. First of all, it is a combinatorial problem with uncertain input data. Secondly, the assembly quality evaluation demands the time-consuming computations of the stress-strain state of the fastened parts caused by sequential installation of fasteners. Most commonly used strategies (heuristic methods, approximation algorithms) require a large number of computational iterations what dramatically complicates the problem. The paper presents the efficient methods of fastener sequence optimization based on greedy strategy and the specifics of the assembly process. Verification of the results by comparison to commonly used installation strategies shows its quality excellence.


2021 ◽  
pp. 102854
Author(s):  
Yunus Emre Bozkurt ◽  
Alptekin Yíldíz ◽  
Özlem Türkarslan ◽  
Feride N. Şaşal ◽  
Hulya Cebeci

1999 ◽  
Author(s):  
Alan M. Tom ◽  
Akihisa Kikuchi ◽  
John P. Coulter

Abstract The current investigation focused on contributing to the development of a novel injection molding process by attempting to understand the scientific relationship that exist between the applied vibrational parameters involved in this process and the effect it has on final product polymeric characterization. Although previous and current attempts at understanding the connection between applied oscillatory or vibrational motion to an injection molding process has shown positive quantitative advantages to final product properties, there still exists a void in the scientific explanation on a molecular level linking these effects. This experimental study, in particular, involved an evaluation on a range of processing conditions applied to Polystyrene and the effects it produced on resultant product quality and polymer properties. Optimal control and mechanical vibrational molding conditions were obtained for Polystyrene. As a result of this, optimal opportunities for initial commercial utilization of the technology can be proposed.


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