Peridynamic modeling of fire damage in composites

Student thesis: Doctoral Thesis

Abstract

The predictions of composite materials responses in fire environments are important in terms of safety. This reality problem can be simplified as a thermal fluid-structure interaction problem in terms of mathematical modelling. The thermo-fluid model is used to simplify the physical properties of fire. The classical continuum mechanics has difficulty in predicting crack propagations because of the singularities of differential equations at discontinuities. Therefore, the peridynamic theory which uses the integral governing equations is a good choice to predict the damage in composite materials. It will bring convenience to simulate the composite response in fire environments using a monolithic methodology. Consequently, in the current study, both thermo-fluid modelling for fire and thermomechanical damage modelling in composites are simulated by using peridynamic theory. Therefore, the following models are developed step by step to achieve the final target.Firstly, a fully coupled thermomechanical ordinary state-based peridynamic model is developed for isotropic materials. Both the deformation effect on the temperature field and the temperature effect on deformation are taken into consideration. Then the fully coupled ordinary state-based peridynamic model for isotropic materials is extended to laminated composites. Besides, a bond-based peridynamic laminate model was applied to predict the responses of a 13-ply composite under a pressure shock loading. Secondly, regarding the fluid model to represent fire, a peridynamic model is developed for Newtonian single-phase fluid low Reynold’s number laminar flow. The high temperature should also be considered which is one of the typical properties of fire. Therefore, the heat transfer is incorporated into the fluid model to represent the thermal properties of fire. Based on the single-phase fluid peridynamic model, peridynamic model for multi-phase fluid flows is also developed.The Navier-Stokes equations including the surface tension forces are reformulated into their integral forms. Thirdly, by combining the developed single-phase fluid peridynamic model and the ordinary state-based peridynamic solid model, a fluid-structure interaction model is developed for the simulation of weakly compressible viscous fluid and elastic structure interactions. Subsequently, the heat transfer is incorporated into the fluid-structure interaction model to predict the composite response under a fire scenario. The ISO temperature-time curve is utilized to present the high temperature which is induced by fire. The thermal degradation properties of the composite materials are also included in the numerical peridynamic composite model. Finally, the composite response underfire scenario is predicted.
Date of Award28 Jul 2020
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsUniversity of Strathclyde
SupervisorSelda Oterkus (Supervisor) & Erkan Oterkus (Supervisor)

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