Evaluate the Mechanical and Thermal Behavioural Deformation of Auxetic Composite Nano-Carbon Fibers

This study aims to identify the composition of the pyrolysis products obtained through pyrolysis in the structure of different auxetic designs. Two design specimens of auxetic nano-carbon fibers with different directional load were fabricated, solid carbon fibers and hexagonal auxetic carbon fibers. The deformation behavior is well-known and has been analyzed. 3D finite element (FE) models were used to investigate both structures. There was some impact on the specimens used, and the behavior of the strain and stress line was captured. The main purpose of the experiment was to define and test the auxetic structure’s use in industries that require nano-carbon fiber material that has excessively good mechanical and thermal properties. In order to prevent the deterioration of the properties caused by this phenomenon, sizing of the yarns and bundles was carried out. Moreover, to form a sizing coating on the elementary fibers, DMA tests have been conducted, and both the thermal and mechanical properties investigated. In this case, the sizing agent must be in a sufficiently softened state. The compositions can improve nano-carbon vs the adhesion of the polymer matrix for auxetic nano-carbon fibers, which allows the use of such fibers for the reinforcement of plastics without extra processing.

Active membranes: 3D printing of elastic fibre patterns on pre-stretched textiles

There has been a steady growth, over several decades, in the deployment of fabrics in architectural applications; both in terms of quantity and variety of application. More recently, three-dimensional printing and additive manufacturing have added to the palette of technologies that designers in architecture and related disciplines can call upon. Here, we report on research that brings those two technologies together – the development of active membrane elements and structures. We show how these active membranes have been achieved by laminating three-dimensional printed elasto-plastic fibres onto pre-stretched textile membranes. We report on a set of experimentations involving one-, two- and multi-directional geometric arrangements that take TPU 95 and polypropylene filaments and apply them to Lycra textile sheets, to form active composite panels. The process involves a parameterised design, actualised through a fabrication process including stress-line simulation, fibre pattern three-dimensional printing and the lamination of embossed patterns onto a pre-stretched membrane; followed by the release of tension afterwards in order to allow controlled, self-generation of the final geometry. Our findings document the investigation into mapping between the initial two-dimensional geometries and their resulting three-dimensional doubly curved forms. We also reflect on the products of the resulting, partly serendipitous, design process.

Residual Stresses Distribution Measured by Neutron Diffraction in Fabricated Square High Strength Steel Tubes

Engineers are increasingly encouraged to consider sustainability in the design and construction of new civil engineering infrastructure. Sustainability can be achieved through the use of high strength materials thereby reducing quantity of materials required in construction where possible. Knowledge of residual stresses in fabricated columns is important in identifying whether the fabricated columns can be classified as heavily welded (HW) or lightly welded (LW). The determination of residual stresses can be used to determine the local buckling of stub columns. Residual stress magnitudes are also essential in the numerical modelling of buckling behaviour of columns. This paper outlines the challenges in measurement of residual stresses using neutron diffraction in fabricated high strength steel square tubes. The residual stress line scans and maps were measured using the Kowari Strain Scanner located at the Australian Nuclear and Science Organisation (ANSTO) in Australia.

Hardness Test on an Epoxy Mold Compounds of a Quad Flat No Lead Package Using the Depth Sensing Nanoindentation

This study focuses on the effect of stress and load towards hardness at epoxy mold compounds (EMCs) of a Quad Flat No- Lead (QFN) package using indentation technique. A series of three points bending cyclic test were performed with four different loads between 60 N to 120 N on QFN package. The nanoindentation with the maximum load of 300 mN was indented at five locations that perpendicular to the stress line on EMCs of QFN package after three points bending cyclic test were performed. The findings showed that the mean value of hardness was varied with load and stress. Higher load and stress were found to be not affected by hardness of EMCs. From the results, it is believed that the applied load and stress not play a role towards the hardness of EMCs. A polynomial relationship was plotted and shown that correlation of coefficient (R2) between stress and hardness of the studied EMCs was found to be at 97%. Finally, the finding suggested that a close correlation between the stress and hardness since it correlation coefficient gave a higher value with the polynomial relationship.