Fiber-reinforced materials are widely used in many industrial applications including civil engineering, automotives, marine, aviation, etc. This is due to their high strength to weight ratios compared to metal structures. One of the major applications of composites is the structural components for automotives such as bumpers, fenders, hoods, door panels. For such applications, impact strength is required since it is directly related to the passenger safety requirements. Sandwich structures are extensively used in automobiles; the understanding of their behaviors under impact conditions is extremely important for the design and manufacturing of these engineering structures. In this study, 27 types of woven fabrics were produced using polyester fibers as warp threads with different structure parameters such as weft yarn material, picks densities, and weaving structures to be used as skin layers and nonwoven fabric was used as core layer. The sandwich composite specimens were prepared using the said woven fabrics with two types of thermoset resins and fabricated via the hand lay up method. The impact properties of the sandwich specimens produced were evaluated to choose the best samples performance to be used in automotive applications. It was found that the impact properties are strongly affected by woven fabric structure parameters and the resin properties.

The stress transfer mechanism in uniaxially and biaxially stretched polymeric geogrids are largely dependent on the interlocking mechanism between the soil and reinforcement. Over the years, this mechanism which may be termed the static interlock mechanism, has been researched and gained wide recognition. When pre-stretched polymeric geogrids are subjected to repeated loading cycles such as compaction forces, a second mechanism which may be termed the dynamic interlock mechanism is developed. In this paper, the existence of this mechanism is established through a series of in-air and in-soil static and dynamic tensile load tests using uniaxially pre-stretched HDPE geogrid specimens. The series of tests also identifies the importance of proper positioning of strain measuring instruments along reinforcements used in reinforced soil structures.

The structural changes brought about by introducing different nitrogen containing groups via cyanoethylation, carbamoylethylation and carbamation in the molecules of rice and maize starches and oxidized starches derived thereof and the onset of these changes on the technical properties of yarns sized with such starch products were investigated. It was found that the apparent viscosity of pastes prepared from those products depends on the nature of starch, the degree of oxidation prior to chemical modification, the nature of modification as well as the measuring conditions, i. e. the rate of shear and temperature. Cotton yarns sized using these starch derivatives were measured for yarn number, tensile strength, C.V.%, elongation at break and C.V.% in elongation. Besides, the weavability test expressed as the minimum number of cycles due to abrasion (St1) and average number of cycles due to abrasion (St6) were investigated. A comparison among modified starches prepared from rice starch would reveral that the highest value of St1 is obtained with yarns sized using carbamoylethylated sample derived from unoxidized starch. With maize starch, on the other hand, the highest value of St1 is obtained with cotton yarns sized using carbamoylethylated starch derived from starch oxidized by 1 g/l active chlorine.

Purpose The paper aims to use the Trilobal® polyester (Y cross-section) for producing fabrics suitable for fencing suits and evaluating their various properties. Design/methodology/approach Double weave structure was chosen to produce the samples by using six different face structures and two back structures divided into two groups according to the back structures. They were evaluated by their physical and mechanical properties such as tensile strength, puncture resistance, air permeability and humidity properties in horizontal and vertical wicking, drying rate and water vapor transmission. Findings Fencing sport recently is one of the most growing sports in the world, which necessitates special requirements and properties of fencing suit, either mechanical properties, which allow the easily and freely movement for the athlete, or the comfort properties that save the player’s effort and energy for a long time to improve his performance. Originality/value ANOVA test analysis showed highly significant results in some properties comparing back and face structures of the double weave fabric high correlation coefficient were found between packing density factor of produced fabric and the weft material types. The final results showed the produced sample that weaved with plain 1/1 for back structure and warp rib 2/2 for face structure achieved the best results, followed by the produced sample weaved with plain 1/1 for back structure and weft rib 2/2 for face structure compared with the other produced samples.

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