Numerical Modeling and Experimental Investigation of Effective Elastic Properties of the 3D Printed Gyroid Infill

A numerical homogenization approach is presented for the effective elastic moduli of 3D printed cellular infills. A representative volume element of the infill geometry is discretized using either shell or solid elements and analyzed using the finite element method. The elastic moduli of the bulk cellular material are obtained through longitudinal and shear deformations of a representative volume element under periodic boundary conditions. The method is used to analyze the elastic behavior of gyroid infills for varying infill densities. The approach is validated by comparing the Young’s modulus and Poisson’s ratio with those obtained from compression experiments. Results indicate that although the gyroid infill exhibits cubic symmetry, it is nearly isotropic with a low anisotropy index. The numerical predictions are used to develop semi-empirical equations of the effective elastic moduli of gyroid infills as a function of infill density in order to inform design and topology optimization workflows

Integration of Material Characterization, Thermoforming Simulation, and As-Formed Structural Analysis for Thermoplastic Composites

An improved simulation-based thermoforming design process based on the integration of material characterization and as-formed structural analysis is proposed. The tendency of thermoplastic composites to wrinkle during forming has made simulation critical to optimized manufacturing, but the material models required are complex and time consuming to create. A suite of experimental methods has been developed for measurement of several required properties of the molten thermoplastic composite. These methods have the potential to enhance thermoplastic composites manufacturing by simplifying and expediting the process. These material properties have been verified by application to thermomechanical forming predictions using commercial simulation software. The forming predictions showed improved agreement with experimental results compared to those using representative material properties. A tool for using thermoforming simulations to inform more accurate structural models has been tested on a simple case study, and produced results that clearly differ from those of models using idealized fiber orientations and thicknesses. This provides evidence that this type of as-formed analysis may be necessary in some cases, and may be further investigated as an open source alternative to commercial analysis software

Critically Vulnerable Coastal Areas - A Framework for Community Based Resource Management: Vembanad, Kerala 2016

The Sustainable Development Goal (SDG) 14 emphasizes Conservation and Sustainable use of the oceans, seas and marine resources for sustainable development. Further, India's National Conservation Strategy and Policy Statement on Environmental and Development, 1992 and the National Environmental Policy, 2006 recognize the importance of multi stakeholder partnership in implementation of conservation plans for sustainable development of natural resources

Progressive failure analysis of three-dimensional woven carbon composites in single-bolt, double-shear bearing

AbstractA three-dimensional progressive damage model has been developed to capture the onset and initial propagation of damage within a three-dimensional woven composite in a single-bolt, double-shear joint. Reinforced with a three-dimensional woven ply to ply interlock IM7 carbon fiber preform impregnated with toughened epoxy resin and manufactured using a resin transfer molding process, the composite represents a unique material currently used in select aerospace structures. The modeled joint is commonly found in many aerospace structures and, when combined with the progressive damage response of this three-dimensional woven composite, the material response can be reliably predicted with a three-dimensional non-linear finite element model. This model is constructed using an orthotropic material assumption far from the bearing area and a voxelized mesoscale model with an as-molded geometry representing matrix and impregnated tow phases. The well-established Hashin failure criteria and the Matzenmiller–Lubliner–Taylor damage model were implemented with the unique morphology of three-dimensional woven composites. The onset of damage and trends seen in the model were found to be in agreement with previous experimental findings