Semi-empirical numerical modeling for optimal production and mechanical behavior of particle reinforced biocomposite
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Date
2019
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Publisher
Universiti Teknologi Malaysia
Abstract
Natural materials as reinforcement replacing the synthetic types reinforcement in composite structures are actively investigated lately for new structural and material development. However, the inclusion of natural materials in polymer matrix often results in poor interfacial interaction due to their different polarities. The drawback of using natural materials can be overcame by employing the reinforcement particle of nano sizes. Yet, there is no numerical study that correlates the effects of interfacial interaction and particle size on their contribution in the tensile modulus formulation. In the current practice, different materials for reinforcement and matrix have been randomly selected without an educated estimate while ignoring also their compatibility. This causes the composite properties to be known only after being tested experimentally. Hence, it is more effective to determine the composite properties by developing a computer program with characterization capability beginning from the production stage of the reinforced material to the confirmation of the materials compatibility as a mixture before going for the prediction of their mechanical behaviors. This forms the motivation for the current thesis study. The essential focus is modeling various parameters of the particle reinforced biocomposite (PRBC) through programming via Matlab software. First, the particle size distribution (PSD) model was developed by employing a semi-empirical size-mass balance equation. In this development, the data-conforming parameters determination technique combining with the average of linear and natural logarithm functions was proposed. The cumulative PSD rates were also suggested as an indicator for the limit of particle size reduction of materials to prevent agglomeration. The new tensile modulus formulation was developed considering the effects of interfacial interaction and particle size. The contribution term of the interfacial interaction effects has been developed by conducting surface wettability analysis. Also, experimental works via digital image correlation coupled with tensile machine were carried out on PRBC for different sizes of rattan to obtain the contribution term of particle size effects. The newly developed tensile modulus formulation was then employed in the two-dimensional elastic plane stress model of PRBC constructed based on the element-free Galerkin (EFG) method. This numerical model was then used to investigate the effects of particle distribution in the biocomposite as well as to conduct the parametric studies, followed by developing the design charts for future applications. Mean absolute percentage error of less than 3.08% has been found showing the high accuracy of implementing the currently developed PSD model. The determination of optimal grinding time was also offered in the study. The new tensile modulus formulation was successfully developed with good agreement against those of experimental works with difference percentage of less than 4%. The predicted tensile modulus of the PRBC modeled by the EFG method is in excellent agreement with those of experimental works. Design charts have been successfully developed based on the parametric studies and can be employed for future analysis and design purposes, particularly, for the PRBC with rattan reinforcement or any materials with similar properties as rattan.
Description
Thesis (PhD. (Civil Engineering))
Keywords
Composite materials—Analysis, Composite materials—Research