Abstract: This paper presenting the effect of corrugation geometry on the crushing behavior, energy absorption, failure mechanism, and failure mode of woven roving glass fibre/epoxy laminated composite tubes subjected to lateral compression load. A comprehensive experimental program has been carried out on three geometrically different types of composite tubes: radial corrugated composite tubes, cylindrical composite tubes, and corrugated surrounded by cylindrical tubes. The three structures are made of woven roving glass fibre/epoxy 600 g/sqm. All specimens fabricated under the same conditions with a fixed number of layers equal to six.

Modeling of take-off and landing motion for a fixed wing (UAV) is necessary for developing an automatic take off and landing control system (ATOL). Automatic take off and landing system becomes an important system due to wide spread of unmanned aerial vehicles in different applications ranging from intelligence, surveillance, up to missile firing. Automatic take off and landing system reduces damage to an unmanned aerial vehicle and its payload that may be caused by human pilot errors. Furthermore, training human pilot to a sufficient level of skill and experience for takeoff and landing may take several years and significant cost. A human pilot also may impose additional restrictions for UAV operation especially at night time or dusty desert conditions. Although, ATOL adds complexity to the system, it reduces the long run cost and risk caused by takeoff and landing process, and makes UAV takeoff from different runways and at different atmospheric conditions. A mathematical model for takeoff is successfully developed for a small fixed wing UAV. A Matlab/Simulink simulation model is prepared for the ground roll phase, and some simulation results are also shown.

Abstract

This paper presents the quasi-static crushing performance of corrugated composite tube with triangular profile. The idea is to understand the effect of corrugation profile on the energy absorption capability of corrugated composite tube of triangular profile with multi layers. Different corrugated composite tubes of triangular profile have been fabricated by hand lay-up technique using woven roving fiber glass/epoxy. Several quasi-static tests have been conducted. for all six shapes of tested models under same conditions. Results showed that the crushing characteristics and energy absorption is highly affected by corrugation profile. 

Abstract

This paper presents the effect of corrugation geometry on the crushing behavior, energy absorption, failure mechanism, and failure mode of woven roving glass fibre/epoxy laminated composite tube. Experimental investigations were carried out on three geometrical different types of composite tubes subjected to axial and lateral compressive loadings. On the addition to a radial corrugated composite tube, cylindrical composite tube, and corrugated surrounded by cylindrical tube were fabricated and tested under the same condition in order to know the effect of corrugation geometry. The results showed that the loading carrying capability is significantly influenced by corrugation geometry in axial crushing. However, no affect of corrugation geometry was observed for lateral crushing. Load–displacement curve was plotted for all conducted tests, thus clear comparison between different specimen's geometry was achieved. It is also found that radial corrugation could significantly applicable as a stable and effective energy absorber.

The purpose of this work is to investigate the effect of the dimensions of composite tubes on their specific energy absorption capacity. Experimental investigations were carried out on three geometrical different cylindrical composite tubes subjected to compressive loading. More over a radial corrugated composite tube was subjected to the same load conditions in order to examine the varying of shape influence on the energy absorption of composite materials. Initial results indicate that for cylindrical tubes, diameter to thickness ratio has a significant effect on the energy absorption. Reduction in tube d/t ratio results in an increase in energy absorption. More over results show also radial corrugated composite tubes exhibit higher total energy absorption than cylindrical composite tubes.

This research is devoted to investigate the effect of structural geometry on the crushing behaviour, energy absorption, failure mechanism, and failure mode of radial corrugated composite shells. A multi-discipline literature review on the use of composite materials in the field of crashworthiness was carried out. Based on the literature review findings, new composite structure (Radial Corrugated Composite Tube RCCT) was proposed to be fabricated and investigated experimentally.

In this article an investigation was conducted to evaluate the level of conformity of reinforcing steel rods produced from recycled scraps by Zliten Steel Factory (ZSF) with relevant to Libyan specifications and international standards. A series of experimental tests were conducted to find ultimate tensile strength (UTS), yield strength (YS), and hardness. Bending test has been conducted too. Reinforcing steel rods samples of 12 and 14 mm diameter were subjected to mechanical properties investigations. The tests were carried out for samples selected randomly through three batches at different time. Obtained results were compared with Libyan specifications (LNS-75) and ASTM standard (A-615). Results showed that the locally produced reinforcing steel were conform with the Libyan and international standards in terms of yield stress, ultimate tensile stress, and hardness.

Abstract:

A detailed experimental investigation of the quasi-static lateral crushing of composite cylindrical tubes between flat platens has been carried out. Tubes employed were made of glass fibre reinforced with epoxy. Behaviour of tubes as regards the peak crushing load, post collapse load, energy absorbed and mode of crushing has been discussed. The load displacement response is plotted graphically.

Abstract

This paper is devoted to study the effect of corrugation geometry on the crushing behavior, energy absorption, failure mechanism, and failure mode of woven roving glass fibre/epoxy laminated composite tubes. A comprehensive experimental program has been carried out on two geometrically different types of composite tubes subjected to axial compressive loading conditions. A cylindrical composite tube has been fabricated and tested in order to provide a means of comparison with corrugated composite tube. Both are tested under the same condition to establish the effect of corrugation geometry. The results showed that the initial failure was dominated by interfacial failure, while a folded zone grows progressively down in a form of mushrooming failure. The results also showed that radial corrugated composite tube (RCCT) exhibited good energy absorption capability than circular composite tube (CCT).

Abstract: The purpose of this work is to investigate the effect of the dimensions of composite tubes on their specific energy absorption capacity. Experimental investigations were carried out on three geometrical different cylindrical composite tubes subjected to compressive loading. More over a radial corrugated composite tube was subjected to the same load conditions in order to examine the varying of shape influence on the energy absorption of composite materials. Initial results indicate that for cylindrical tubes, diameter to thickness ratio has a significant effect on the energy absorption. Reduction in tube d/t ratio results in an increase in energy absorption. More over results show also radial corrugated composite tubes exhibit higher total energy absorption than cylindrical composite tubes.