Department of Mechanical Engineering
Research and Characterization of Composites and Polymers Lab
Research and Characterization of Composites and Polymers Lab

Research

Composites

Background

Continuous technological innovation has pushed the physical limitations of conventional materials, and required the development of new material solutions to meet application demands. Composite materials have emerged as an increasingly common replacement for metals in many structural components. Their high specific stiffness-to-mass ratio, in particular, has made them ideal candidates in the aerospace, automotive, biomedical, military, and renewable energy industries. Despite their desirable material performance, however, the anisotropic nature of composites prohibits the usage of well-studied models for isotropic material behavior. The practical implementation of composite materials into engineering applications requires the development of new, economic methods to simulate their design and failure. The RECCAP Lab works in conjunction with Imperial College in London, UK to design, fabricate and characterize new composite materials.

Research Goals

Fatigue modeling of fiber reinforced composites (FRC)

  • Characterize fatigue behavior of FRCs under cyclical loading
  • Predict fatigue life of various FRCs
  • Methods: low cycling (LCF) and high cycle (HCF) fatigue loading

Composite laminate stacking optimization

  • Develop adaptive genetic algorithms (AGA) to optimize FRC stacking sequences
  • Predict the optimum sequence for both in-plane extensional stiffness and laminate bending stiffness
  • Methods: adaptive genetic algorithms, finite element modeling

Collaborators

Liquid Crystalline Polymers and Electronics Packaging Materials

Background

Liquid crystalline polymers (LCPs) comprise a class of performance materials with specialized properties, including high mechanical strength at high temperatures, chemical inertness, flame retardancy and frequency-stable dielectric properties. Because of these favorable characteristics, LCP's are ideal candidates for various engineering applications, such as electronics packaging, high-frequency sensors, and high strength-to-weight ratio components. This distinctive material behavior arises from the molecular orientation that shares characteristics of both a conventional amorphous polymer and a crystalline material; in both the melt and solid phases, the polymer chains exhibit a degree of long-range order. This unique LCP microstructure, despite driving the desirable macroscopic behavior, also leads to intrinsic anisotropy in the polymer. Such directionality in properties can pose potential issues for applications requiring homogenous material performance, and thus the ability to characterize, predict, and control the LCP morphology is crucial to meet practical manufacturing demands. The RECCAP Lab serves as a world leader in LCP expertise, with more thesis projects over its 25-year history than any other academic institution. Additionally, the RECCAP Lab has pioneered the electronics packaging field through the development of novel nano-filled LCPs and ductile sub-layers to optimize integrated circuit performance.

Research Goals

Thermal and electrical characterization of LCPs

  • Understand the effects of processing (extrusion, injection molding) on LCP coefficient of thermal expansion (CTE) and dielectric behavior
  • Investigate material thickness and skin-layer thickness effects on CTE and dielectrics
  • Methods: thermomechanical analysis (TMA), resonant cavity perturbation method

Directionality modeling of LCPs during steady-state processing

  • Simulate the evolution of directionality in LCPs during extrusion
  • Understand and predict factors affecting LCP crystal orientation, both inherent to the polymer, and induced during manufacturing
  • Enable rapid extrusion die evaluation and manufacturing process design
  • Methods: CFD, numerical directionality modeling

Electronics packaging materials development and implementation

  • Minimize thermal stresses in integrated circuits through the implementation of ductile sub-layers
  • Improve optical properties of LED devices using nano-filled LCP packaging materials
  • Methods: finite element modeling, image analysis

Energy Storage Materials and Batteries

Background

Incremental improvements in recent years have sought to alleviate the significant technical limitations that batteries face relative to safety, cost, and energy density. In typical liquid electrolyte cells, the electrolyte serves as a medium for ion transport involved in the cell charging/discharging cycle, and a polymer or ceramic separator must be used to electronically isolate the anode from the cathode. However, both functions of ion conduction and separation can be realized in a single thin membrane when solid polymer electrolytes are used. Additionally, these membranes benefit from the ease of processability, design flexibility, light weight, shape versatility, safety, and nontoxicity, of typical polymer films, with the electrical properties of the traditional liquid electrolytes. The research and development of energy storage materials and batteries is a new and expanding area of research for the RECCAP Lab.

Research Goals

Characterization of solid polymer electrolyte dielectric properties and ionic conductivity

  • Utilize novel non-contact testing method to measure polymer electrolyte dielectric properties, and thus derive the electrolyte ionic conductivity

Collaborators