China
Africa
Explore chapters and articles related to this topic
Measuring stiffness of soils in situ
Published in Fusao Oka, Akira Murakami, Ryosuke Uzuoka, Sayuri Kimoto, Computer Methods and Recent Advances in Geomechanics, 2014
Fusao Oka, Akira Murakami, Ryosuke Uzuoka, Sayuri Kimoto
In the multiphase mixture theory, it is fundamentally assumed that each phase is not mixed together and the whole mixture is represented as the sum of each phases interacting together. Frozen soil is approximated as the soil-water-ice three-phase mixture as shown in Figure 1. The partial density of phase- α:ρα(s,w and i see Figure 1) is defined in terms of its volume fraction and material density: ρα, and the total density of the whole mixture: ρ is given as the sum of its partial densities: ρs=(1-n)ρx,ρw=n1-Siρwandρi=nSiρρ=∑aρα=(1-n)ρs+n1-Siρw+nSiρ'
Low velocity impact response and influence of parameters to improve the damage resistance of composite structures/materials: a critical review
Published in International Journal of Crashworthiness, 2022
Kiran Kaware, Mangesh Kotambkar
The matrix materials, reinforcing elements, and distribution and arrangements of the reinforcing constituents for the composite materials are faithfully represented by previous microscale models but it cannot directly use in the design and analysis of composites. Also, semi-empirical macroscale models cannot precisely capture the complicated impact behaviour of composites as featured with viscoelasticity, viscoplasticity, thermoelasticity, thermoplasticity, and damage. Due to which these models unable to simulate the failure modes like fibre breakage, matrix cracking, deterioration in the reinforcing element-matrix interface. To fill this gap, He et al. [55] developed a multiphase constitutive modelling framework using Internal State Variable (ISV) theory that uses the microstructure-property relationship of the composite materials to predict their impact response and failure modes. This model integrates mixture theory which combines the individual material constituent formulation to study the behaviour of FRP composites. For identification of initial yielding of material, the rate-dependent yield surface is used. For the application of this ISV model, Polyamide 6,6 reinforced with glass fibre and GFRP examples are used to describe the different behaviour of composite. In the constitutive model of short fibre reinforced polymers (SFRPs), the moisture effect for different strain rate and fibre content is considered. This model is based on the modelling of material degradation due to the absorption of moisture of composite. It accurately predicts the complex behaviour of SFRPs [56]. In comparison to other models, it is seen that this is a macroscale continuum framework that sense homogenises microstructural features of material systems and can have wide application for designing a variety of composite materials with different constituents. Also, the Strain rate effect which is integrated with this model by using strain rate ISV plays an important role that influences the impact response of composites [57,58].