20-10-2010, 04:41 PM
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Toward Functionally Graded Cellular Microstructures
Presented by:
Balasubramaniam
M.Tech-Machine Design (1st Year)
Karunya Institute of Technology.
Guided by:
Mr. Prancis D’Souza
Lecturer,
Mechanical Department,
IIT Kanpur.
SYNOPSIS
Why towards this topic?
The design of multifunctional materials offers great potential for numerous applications in areas ranging from biomaterial science to structural engineering.
- What are functionally graded cellular microstructures?
• Functionally graded microstructures (e.g., polymeric foams) are those whose porosity (i.e., ratio of the void to the solid volume of a material) is engineered to meet specific requirements such as a superior mechanical, thermal, and acoustic behavior.
- What does this paper describe?
• This paper describes work to develop an innovative and flexible process for manufacturing engineered cellular structures.
- What is the technology used?
• Ultrasound is applied during specific foaming stages of a polymeric (polyurethane) melt, and this affected both the cellular architecture and distribution of the pore size, resulting in a controlled distribution that can be designed for specific purposes, once the polymeric foam solidified.
- The result of this paper.
• The experimental results demonstrate that porosity (i.e.,volume fraction) varies in direct proportion to the acoustic pressure magnitude of the ultrasonic signal.
CONCLUSIONS
• The effects of ultrasound on porosity demonstrated by this work offer the prospect of a flexible manufacturing process that can control and adjust the cellular geometry of foam.
• Further work needs to be done in order to investigate if other polymers’ “sonication window” allows ultrasound to produce a long-lasting effect once the solid structure is set, and if ultrasonic irradiation can also be used as a porosity-tailoring agent when polymers are manufactured under different conditions of pressure, temperature, etc.
