Thermal analysis and design of a multi-layered rigidity tunable composite

W. L. Shan, T. Lu, Z. H. Wang, C. Majidi

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

Elastomer-based composites embedded with thermally-responsive material (TRM) and a liquid-phase Joule heater are capable of reversibly changing their elastic rigidity by up to four orders of magnitude. At room temperature, the TRM layer is rigid and prevents the surrounding elastomer from elastically bending or stretching. When activated, the embedded Joule heater softens or melts the TRM, which leads to a dramatic reduction in the elastic rigidity of the composite. In this manuscript, we examine the activation of these composites by performing analytical, numerical, and experimental studies of the temperature distribution, thermal history, and phase transition. We consider both low melting point (LMP) metal alloys (e.g. Field's metal) and shape memory polymer (SMP). An analytical solution using the Galerkin Based Integral (GBI) method is derived for the cases where no phase change is involved, while a numerical scheme using the Latent Heat Accumulation (LHA) method is utilized to probe scenarios where phase change has a central role in the elastic rigidity change. The analytical and numerical studies predict a temperature history that is in good agreement with experimental measurements obtained with an IR thermometer. Analysis of the internal temperature distribution leads to scaling laws for determining the required activation time and allowable input power rate for composites containing either LMP alloys or SMP. These scaling laws could potentially be used to inform the design of rigidity tunable composites (RTC) used in assistive wearable technologies and biologically-inspired soft-matter robotics.

Original languageEnglish (US)
Pages (from-to)271-278
Number of pages8
JournalInternational Journal of Heat and Mass Transfer
Volume66
DOIs
StatePublished - Aug 14 2013
Externally publishedYes

Keywords

  • Joule heating
  • Latent heat accumulation
  • Low melting-point alloy
  • Phase change
  • Rigidity tunable composite
  • Shape memory polymer

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

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