Applied Mechanics and Materials Vol. 815

Abstract: Commercial aviation is experiencing the fast growth exceeding automotive travel; the latter is well known for contributing to air pollution. Commercial aviation impacts climate by two main avenues: the emission of greenhouse gases and cloud effects. While the former impact is similar to other activities that contribute to anthropogenic climate change, the latter is unique to aviation. Anthropogenic solutions that can be offered by Aerospace Technology to address anthropogenic environmental changes, known as green technology initiatives, may only provide partial or temporary solutions. In the efforts to intervene such process and thus maintaining the sustainability of the earth’s environment, some scientific and technological guidelines to comprehend the natural phenomena and global changes are reviewed and discussed. Selected efforts devoted to aircraft technology and aviation, for maintaining the sustainability of the earth’s environment are elaborated. Particular considerations are given to fuel burn affecting greenhouse gases and cloud effects due to trailing vortices and hence contrail.

Abstract: Pressure garment is a standard non-surgical treatment for hypertrophic scar caused by burn injury. However, the main problem identified was the non-uniform pressure distribution due to the complexity of the contour at the facial area. Therefore, padding was developed to produce more efficient pressure distribution. This study used 3D scanning apparatus to obtain the cross sections of the facial area. The padding was developed using 3D modeling software which act as an insert to fill the gaps at the contact area of the garment and facial areas. The result shows that by inserting the padding underneath the garment, the pressure outputs indicate an acceptable pressure range with the suitable reduction factor for the head garment fabrication.

Abstract: This paper utilized a simulation software to determine an optimal buffer allocation for any unpaced production line when a set of buffer quantity is known. The optimal buffer allocation will give the highest throughput rate (productivity) to the production line. From the simulation result, a trend of relation between mean processing time (μ) trend of the stations in the production line and buffer allocation configuration of the buffer slots were studied. It was concluded that for any unpaced production line, the best throughput rate of the production line will be obtained if the buffer allocation configuration follow the mean processing time (μ) trend. By applying this concept, a mathematical relation was formed results in a development of a technique called 6 Steps OBA (optimal buffer allocation) method . In order to validate the result from this 6 Steps OBA method, a case study was carried out in one of the multinational electronics company in Malaysia (Company S). An unpaced and u-unbalanced production line was selected and this line was producing a product which is known as model A. In this production line, a few possible buffer allocations quantity were allocated on each buffer slots including buffer allocation suggested by 6 Steps OBA method. For each buffer allocation possibilities, the actual production line productivity (throughput rate) was recorded and compared to validate that the best line throughput rate was the buffer allocation suggested by the 6 Steps OBA method. From the overall result, it was proven that the 6 Steps OBA method will give a maximum throughput rate to a production line.

Abstract: The primary purpose of this project is about simulation and experimental studies for optimum barrel length of a high impact penetrator.This project uses the concept of two-stage light gas gun modified by using shaped charge at the first stage. Sacrificial barrel is the important part for this project. The combination of sacrificial barrel with piston serves to compress the air along the barrel at appropriate pressure. It produces sufficient amount of pressure to rupture the rupture disc and the pressure will force the projectile to travel through the barrel. There is some parameter to be investigated such as volume of air in pump barrel, strength of rupture disc and location of the piston in the sacrificial barrel. Some method is use such as calculation to determine the suitable length for the sacrificial barrel and the thickness of the rupture disc. The parameter will be use to perform simulation that will result in amount of the pressure and velocity of projectile that can be produced. The comparison result from simulation and experimental testing on the condition of sacrificial barrel and piston is obtained in this study. The significance of this project is more on the cost because this project only uses an atmospheric air as a mechanism to launch a projectile. More than that, high impact penetrator can reduce space because it is smaller compare to light gas gun.

Abstract: Determination of specification for product development is useful, as it includes an overview of product-related information. However, it is not an easy thing, especially for new and innovative product. In the view of designer as the subject who has never made the product, he needs to work closely with the manufacturer so that the concept can be designed to become a feasible product. In addition, in order to reduce product design life cycle and minimize design errors, the designer needs to communicate and collaborate with the manufacturer. This research proposes a design specification based on the paradigm of Concurrent Engineering (CE) from Collaborative Product Development (CPD) strategy in the development of a new ergonomically designed Short Wheel Base (SWB) Recumbent Bicycle. This collaborative process involved an expert from bicycle practitioner which already had experience in building custom bicycle. The result of this study is a frame set design of the bicycle which considers human anthropometry and the detail list of its components. Beside of that, the process of collaboration with practitioners bicycle produces 37% change in the components used and 3 changes in shape of design SWB Recumbent Bicycle.

Abstract: The purpose of this study is to identify the quality of the product and the key product features based on customer satisfaction through the Kansei Engineering (KE) and Kano Model (KM). There were 509 respondents involved in this survey to answer the questionnaires developed that contains of 8 shampoo bottles design, 6 words representing emotional quality based on Kansei Words (such as Dull~Attractive; Difficult to Use ~ Easy to Use; Common ~ Unique; Stiff ~ Elegant; Complicated ~ Simple; Awkward ~ Comfortable), and 6 questions towards functional and dysfunctional attributes of quality based Kano method. Mostly of survey respondents feels that the proposed of shampoo bottle designs as 'Indifferent' (I) quality attributes. Also, the results showed that of the “K2” (in-out mechanism toward liquid inside the shampoo bottle) using 'flip top' cap is mostly having siginificant correlation with the design in the eyes of customers based on 'Stiff ~ Elegant' (SE), 'Difficult ~ Easy' to use (DE) and 'Dull ~ Attractive' (DA). This study found and showed the design of products can be interpreted using Kansei Words towards what the articulation of the design profile that represented the customers' emotional design.

Abstract: Surface roughness is an important indicator to assess the surface processing quality and has a decisive impact on the furniture finishing effects. In this research, the application of response surface methodology (RSM) has been carried out for modelling and analysing of influences in the sanding process on wood materials. Surface roughness parameter R_a showed surface characteristics of Tembesu, Jati and Petanang. This study is aimed to observe the effect of feed rate and grit size on R_a. The central composite design (CCD) was used as a design of experiment (DOE). There were 8 runs at factorial points and additional 5 replicated runs at the centre point. The sanding process was done using a modified horizontal milling machine. The results are statistically analysed by using Design Expert software. It was found that increasing of feed rate had a positive effect on the roughness value of R_a and greater feed rates increased the surface roughness. On the other hand, grit size influenced negative effect. Larger grit size affected the smoother surface roughness. At the end of this study, it was also revealed that the optimum machining conditions in terms of feed rate and grit size were 17 mm/min and 240 for Tembesu and Jati, while Petanang was 18.63 mm/min and 226.52.

Abstract: The endoskeletal below knee prostheses was commercially available in Indonesia. More advanced products also available in the market but they come with expensive price and high maintenance cost. This paper presents a design concept of an affordable endoskeletal below knee prostheses for daily living with functional ankle joint. The design was developed through the application of appropriate technology approach from the total ergonomics framework which consists of 7 characteristics; technically feasible, ergonomic, energy saving, economical, socioculturally acceptable, environmental friendly, and trendy. The result is an endoskeletal below knee prostheses with multiaxis joint system and energy store-return components installed on its modular ankle joint.

Abstract: In this paper, we analyze the mismatch between the desk and chair key characteristics and pupil’s anthropometric data. Samples were taken from public elementary schools in six regions (Surakarta, Sukoharjo, Sragen, Karanganyar, Boyolali, and Klaten) of Central Java Indonesia. Mismatch comparisons are made among existing desk and chair, Indonesia National Standard (SNI) dimensions, and the dimensions from pupil’s anthropometric data. Monte Carlo simulation method is used to find the smallest mismatch among the anthropometric percentiles data. From the analysis of simulation result using Crystal Ball software, seat width and under desk clearance have the lowest mismatch. The seat height and desk height from desk and chair dimensions from pupil’s anthropometric data have the lowest mismatch comparing to the existing and SNI desk and chair dimensions.

Abstract: This paper present a study of the 2 dimensional ultrasonic vibration assisted micro-milling (UVAM) focused on the tool motion shape and tool trajectory. The cutting characteristics in 2 dimensional are in view by considering the trajectory of the amplitude of vibration towards tool locus into the workpiece during the tool rotation are explore in depth. The vibration platform travel in X_f direction known as a feedrate movement, thus the X and Y axis vibration generate simultaneously through the workpiece surfaces. Amplitude value acting on X and Y axis proposed a major effect as it will effectively change the shape of tool trajectory between oval and eclipse. This investigation found the major advantages of UVAM is come from the alternating cycle’s gap phenomena between tool and workpiece. The reduction of prediction of cutting force and the thinning chip thickness formations has been observe during the investigation. The theoretical finding will be discussing the potential to extended tool life, surface roughness and material removal rate in the conclusion for future research plan.