• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • Tagged with
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Developement Of Aluminium Foam : An Experimental And Numerical Study

Jha, Kaushal 01 1900 (has links)
Metal foams are lightweight structures and have large use in many components acting as impact energy absorbers. They have exceptional mechanical, thermal and acoustic properties. The design or selection of foam for packaging is done on the basis of impact loads to be sustained or energy to be absorbed. For transportation of nuclear material, metal foams can be used as a packaging material. It may be noted that apart from other qualification requirements, a package containing nuclear material, has to be certified for drop test. Foam can serve the purpose by providing proper cushioning. Metal foams are still under development and need to be accurately characterized in terms of their mechanical properties as well as cell morphology. The aim of this work is to develop, characterize and model foam using experiments and analysis. Aluminum foam has been developed by powder metallurgy technique and the effect of addition of varying amounts of Mg and Alumina on the strength and energy absorption has been studied. Foams of varying densities have also been developed. The reason for going for higher density is to obtain higher plateau stress. If a package is designed with lower density foam, it may become very bulky and even impractical. The characterization part of the work includes study of porosity distribution, cell wall structure, microscopy, SEM images, etc. Mechanical testing (uniaxial compression) was performed on foam samples to get load deflection curve of foams. Area under a given curve i.e. energy absorbed per unit volume has been compared for various compositions and densities. The analysis part of the work presents effect of specimen size on bulk properties of foam. 2D honeycomb and 3D cases have been discussed. To model the porosities, spherical cavities have been assumed. Uniaxial compression cases with different combinations of porosities have been analyzed. The properties like Young’s modulus, plateau stress, Poisson’s ratio, tangent modulus, etc. have been evaluated. The effect of variation in yield strength and tangent modulus of base material on foam has been studied. It appears that if the model is based on uniform porosity distribution, it may lead to lower bound values of physical properties and give conservative result. Although some of these trends have been observed in published literature, the current numerical study has generated additional information and insight.

Page generated in 0.0867 seconds