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Problem statement: In general, the automotive structure is targeted to absorb high impact energy with least mass as much as possible. This is in order to limit the fuel consumption. Therefore, various techniques to increase the energy absorption with less mass increment have been studied for years. One of those techniques is by filling foam in the tube. This study is also aimed to investigate more detail of the behavior of foam-filled structure under impact. Approach: The study was carried out experimentally by using steel tubes of 2 dimensions i.e., 1×2 and 2×2 inch 2 . The thickness of each tube was varied from 1.2, 1.5 and 1.8 mm. Each tube was filled with polyurethane foam. The density of foam was varied from 100, 200 and 300 kg m −3 . The foam-filled tubes were crushed axially using a 1,000 kN universal testing machine. The crush speed was 50 mm min −1 . The load -displacement were recorded and the energy absorption of each specimen was calculated and compared. In this study the specific energy absorption was used as a key indicator, rather than energy absorption, in order to take the mass increment into account. Results: The experimental observation revealed that the structures failed in square mode with number of fold increases as the density of foam increased. It also found that the foam filled tube with density of 300 kg m −3 absorb energy more than that of the tube with foam of 200 and 100 kg m −3 density and empty tube respectively. However, when taking mass into account, the tube with 200 kg m −3 foam-filled may be the most efficient since it provided maximum specific energy absorption value. Conclusion: The result indicated that the density of foam increases the number of folds in collapsed tubes. The result also revealed that tube with higher density foam can absorb more energy absorption. In addition, it was found that the density of 200 kg m −3 is the optimum value to fill in tube since it offers maximum specific energy absorption.

A typical way to produce biodiesel is the transesterification of plant oils. This is commonly carried out by treating the pre-extracted oil with an appropriate alcohol in the presence of an acidic or alkaline catalyst over one or two hours in a batch reactor.Because oils and methanol are not completely miscible. It has been widely demonstrated that lowfrequency ultrasonic irradiation is an effective tool for emulsifying immiscible liquids. The objective of this research is to investigate the optimum conditions for biodiesel production from crude Jatropha curcas oil with short chain alcohols by ultrasonic cavitation (at 40 kHz frequency and 400 Watt) assisted, using two step catalyst method. Usually, the crude Jatropha curcas oil has very high free fatty acid which obstructs the transesterification reaction. As a result it provides low yield of biodiesel production. In the first step, the reaction was carried out in the presence of sulfuric acid as an acid catalyst. The product was then further transesterified with potassium hydroxide in the second step. The effects of different operating parameters such as molar ratio of reactants, catalyst quantity, and operating temperature, have been studied with the aim of process optimization. It has been observed that the mass transfer and kinetic rate enhancements were due to the increase in interfacial area and activity of the microscopic and macroscopic bubbles formed. For example, the product yield levels of more than 90% have been observed with the use of ultrasonic cavitation in about 60 minutes under room temperature operating conditions.

The behavior of foam-filled thin-walled aluminum tube under impact was investigated focusing on different crashworthiness parameter. The diameter to thickness of tube ranging between 26.5 and 200 were filled with polyurethane foam density from 100250 kg·m ¹3. The specimens were crushed by a drop hammer. The result from finite element simulation and experiment was compared and good agreement was achieved. The simulation was also used to conduct further investigation on tube with higher diameter to thickness ratio. It was found that by filling foam, the tubes change their collapse modes from asymmetric mode to axisymmetric mode. Also, the energy absorption can be enhanced by filling tube with higher foam density. The impact energy was found to be managed more efficient in foam filled tube as the load efficiency is higher in higher density foam-filled tube. However, the specific energy absorption of foam-filled tube is getting lower in higher density foam. This paper provides experimental and numerical data as well as discussion in various aspects of crashworthiness.

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