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.

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

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 turbine of an automotive turbocharger is essentially one acoustic element in the exhaust system which lies between the primary noise source, the gas pulsations through the exhaust valves, and the primary noise radiation element, the exhaust tailpipe orifice. As such, like every other acoustic element of the exhaust system, it has a passive effect on the propagation of the primary exhaust noise. Thus if a comprehensive model of the acoustic propagation through the entire exhaust system of a turbocharged engine is sought, an acoustic model of the turbine is a prerequisite.

This paper presents a preliminary attempt to create such a model. The model is a purely fluid mechanic one, without recourse to any empiricism such as a turbine map. The nonlinear equations of the fluid flow are developed and solved for steady flow, to determine the mean convective flow effects upon the noise. The full time-domain equations are then linearised and solved for a single frequency of sound.

Results are given from both the steady flow and the acoustic analyses. The latter are presented in terms of both transmission loss and four-pole parameters. The model is found to give a rational representation of the passive effect of a turbine rotor.

Abstract

This paper presents a one-dimensional acoustic model for prediction of the frequencies of

self-excited oscillation and acoustic mode shapes in combustion systems. The impedance of

the combustion system is represented in terms of a frequency response function (FRF).

Impedances of the settling and combustion chambers are predicted by using the acoustic

model, taking into account the temperature distribution in the combustion chamber. Reasonably

good agreement between measured and predicted acoustic resonance frequencies and

mode shapes was achieved. Some data on stability regimes are discussed.

# 2003 Elsevier Science Ltd. All rights reserved.

Keywords: Combustion; Instability; Eigen-frequencies; Prediction; Measurement

Abstract

Experimental investigations have been carried out to measure axial effective thermal conductivities of

packed beds for a number of particles and catalyst pellets. Measurements were made for three gases (air,

nitrogen and carbon dioxide) in beds packed with ball bearings, copper chromite, chromia alumina, alumina

hollow cylinders and alumina spheres. A glass vacuum vessel was employed for most measurements,

but a thin wall stainless steel vessel was used in a few experiments.

Empirical correlations to predict the axial effective thermal conductivity of packed bed reactors have

been derived from the experimental results.

2002 Elsevier Science Ltd. All rights reserved.

Keywords: Axial thermal conductivities; Packed beds