Author : Thomas John Berton
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (133 download)
Book Synopsis Computational Modelling of Progressive Damage in Viscoelastic-viscoplastic Composite Materials by : Thomas John Berton
Download or read book Computational Modelling of Progressive Damage in Viscoelastic-viscoplastic Composite Materials written by Thomas John Berton and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Current governmental requirements for greater fuel efficiency are pushing automotive manufacturers to find innovative ways of reducing car weight, while still maintaining mechanical performance to ensure passenger safety. Composite materials would allow for significant weight reduction, while still maintaining a safe environment for the passengers. However, composite materials are known to exhibit significant time-dependent behaviour, as well as progressive damage which affect structural performance. Bio-composites in particular are known to undergo complex damage evolution during their lifetime. In this thesis, a multi-scale computational approach has been adopted to take these effects into account. A new modelling approach based on Synergistic Damage Mechanics to understand damage evolution in composite materials undergoing time-dependent deformation is developed. The model is applied to matrix micro-cracking in laminates. Computational micro-damage mechanics is combined with a continuum level description of stiffness degradation to predict the evolution of micro-cracking while requiring minimal experimental calibration. The time-dependent behaviour is modelled using Schapery's theory of viscoelasticity and viscoplasticity, and the evolution of matrix micro-cracking during creep is predicted. The predictions of the model for different stacking sequences, ply thicknesses and working temperatures show that viscoelasticity and viscoplasticity have a significant effect on the long-term response of laminates undergoing matrix micro-cracking. The multi-scale modelling approach is extended to short fiber bio-composites by constructing a micro-damage model of fiber-matrix debonding using a Cohesive Zone Model. The effect of strain rate on fiber-matrix debonding is analyzed by implementing a non-linear viscoelastic model for the matrix, and it is shown that viscoelastic behaviour leads to a competition between void nucleation and debonding. The effects of fiber stiffness, dimensions and interfacial shear strength are evaluated. Following the micro-damage analyses, the thesis focuses on damage evolution at the structural scale by implementing the damage model in Finite Element Analysis software to analyze the dynamic response of a car bumper. The rate-dependent evolution of damage is predicted for different stacking sequences and material systems.