Abstract: In the plastic industry, recycling waste from production is normal practice for reducing waste and cost. When they were reproduced, their mechanical properties are changed. These changes may affect the quality of the end product. Hence, this work studied the mechanical, thermal and rheological properties of recycled biodegradable poly (butylene succinate) (PBS) with reproduction of 10 cycles. The results showed that tensile strength was slightly increased with increasing reproduction cycle until 6th cycles and reduced in the further cycles, respectively. The elongation at break was abruptly decreased with an increase of the cycle number. Moreover, the hardness was quite constant in the lower cycle number but it was slightly decreased in the higher one. Melt flow index (MFI) measurements indicated a significant change in the material after 2rd recycles. The results on thermal properties measurement showed that degree of crystallinity decreased in the 6th cycles.
Abstract: A new type of viscoelastic vibration damping rubber matrix, styrene-butadiene block copolymer with designed molecular weight, unit sequence, mass ratio of styrene/butadiene and content of bound styrene synthesized through anionic solution polymerization method with more excellent damping properties than the current commercialized SBR is exhibited. In addition, the glass transition temperature (Tg) of the new type of SBR can be tunable to the suitable temperature region according to the application requirements. In this paper, we put the emphasis on the synthesis and properties characterization of this new type material, and try to provide a new method to fabricate a viscoelastic damping material (VDM) with tunable Tg and excellent dynamic mechanical properties usable for applications in the field of vibration reduction industry.
Abstract: High velocity impact analysis of natural fiber reinforced composites is essential as the trend is focused towards the development of light weight, environment-friendly, non-corrosive and economical materials. At present, the defence, aerospace and automobile sectors are using synthetic fiber composites which are expensive and non-eco-friendly. In the present study ballistic impact of jute-epoxy (JEC), glass-epoxy (GEC), jute-epoxy-rubber (JERC) sandwich composites are simulated with different thickness (1, 2 and 3 mm) and velocity variations (100, 200 and 300m/s) using Finite Element analysis software. Although different approaches to the analysis of the effect response of composite structures are available, numerical modeling is based on strict constitutive models is often preferred because it can provide valuable detailed information about the spatial and temporal distribution of damage during the impact. The ballistic parameters such as energy absorption, ballistic limit and fracture behaviors are predicted. The composite is made of 8 noded linear brick elements and the bullet/projectile is modeled as a discrete rigid element in which deformation behavior, energy absorption and penetration behaviors obtained are clearly represented. The simulation results predicted match well with the analytical results obtained. Among all the combination of the materials simulated, the sandwiches have better ballistic qualities. Energy absorption of sandwich (JERC) was found 67 percentage higher than GEC and 56 percentage higher than JEC laminate. In future, these materials can be the alternative materials for defence sector for bullet proofing.
Abstract: In this paper, experimental results that illustrate stress softening in carbon filled natural/styrene-butadiene blend rubber (NSBR) together with Mullins effect are introduced firstly. Then, based on these data, the Ogden constitutive model is derived. The theory of pseudo-elasticity is used in the model. It is found that theory of pseudo-elasticity and Ogden constitutive model is applicable in this composite.
Abstract: The aim of this research was to determine the influence of the short carbon fibres in nylon PA6 polymer used for fused deposition modelling (additive manufacturing) technology. Specimens from pure PA6 and PA6 with short carbon fibres were fabricated, with both main directions of the material with respect to the build orientation in a 3D printer. Experimental tensile tests of the specimens were carried out at several temperatures according to ISO standards. The strength, tensile modulus and ductility in relation to the temperature were compared. A significant influence of the short carbon fibres on the strength and heat deflection temperature of the part was found in PA6 and also for the orientation of the build in the 3D printer.
Abstract: Nano composites are finding increased focus and their influence on improving the matrix properties are very attractive. But the success is fully dependent on the uniform distribution and dispersion of nano reinforcements in the matrix. Manufacturing process was found to have greater role in distribution of the reinforcements. The liquid processing and solid processing like SPS and hot coining found to have different effect on the matrix due to the nature of reinforcements. Current study focussed on the microstructure study using Back scattered images and the microhardness with and without reinforcements. MWCNT was occupying the particle boundary. Hot coining was found to distribute MWCNT on the particle surface as well as on the particle boundary. Clustering was absent and resulted in improved hardness in comparison with casting as well as spark plasma sintering.
Abstract: The void formation in FRP composites is unavoidable and the void content measurement is very important to study its deleterious effects on the mechanical properties of the material. Generally destructive methods are used to calculate the void volume fraction. But the recent advances in X-ray computed tomography can be used to detect and quantify the void content in the composites in a non-destructive manner. In this study average area method is proposed and validated for the void volume measurement from the X-ray CT image slices through digital image processing. The effects of void size, shape and position in the accuracy of the measurement is studied and presented here. The void volume fraction of a CFRP laminate manufactured with compression molding technique is calculated by this method and found to be around 1%.
Abstract: This Aluminum alloy matrix composite reinforced with TiB2 particulates with different volume % of TiB2 (5, 10 and 15) has been successfully synthesized by P/M route. The composite powders were consolidated by cold uniaxial compaction pressure followed by sintering at 590 ̊C in nitrogen atmosphere. The effect of reinforcement on the densification was studied and reported in terms of the relative density, densification parameter, tensile rupture strength and Vickers hardness of the composite. The above physical and mechanical properties increase with compaction pressure irrespective of TiB2 content. Scheil cooling and equilibrium calculations were performed using FactSage for qualitative understanding of the microstructural evolution during sintering. The experimental results showed that samples with 5 volume % TiB2 exhibits optimum densities after sintering and correspondingly highest hardness.
Abstract: In the present paper, experimental investigation as well as computer assisted casting simulation technique is used to analyse the effect of different parameters like properties of sand and molding methods to predict defects in green sand casting. An attempt has been made to obtain the optimal settings of the moulding sand and mould related process parameters for the casting of Al-4.5%Cu-2.5TiB2 composites. The green sand related process parameters considered in the study are moisture content, green compressive strength, permeability of moulding sand and mould hardness. In the fabrication of composites, porosity is greatly influenced due to improper gating/riser system design. The analysis of porosity is performed using Auto-CAST simulation technique by the introduction of a new gating system designed and the solid model was developed for sand mould cavity. A number of iterations using Auto-CAST simulation software were performed for mould filling and solidification analysis to reduce the level and intensities of porosities in cast Al-4.5%Cu-2.5TiB2 composite. With new gating and feeding system design, reduction in porosity and improvement in yield is observed. The simulation results were found to be in good agreement when compared with the experimental trial.