Kinematic Synthesis of Planar, Shape-Changing Rigid Body Mechanisms for Design Profiles with Significant Differences in Arc Length

This paper presents a kinematic procedure to synthesize planar mechanisms capable of approximating a shape change defined by a general set of curves. These ``morphing curves'', referred to as design profiles, differ from each other by a combination of displacement in the plane, shape variation, and notable differences in arc length. Where previous rigid-body shape-change work focused on mechanisms composed of rigid links and revolute joints to approximate curves of roughly equal arc length, this work introduces prismatic joints into the mechanisms in order to produce the different desired arc lengths. A method is presented to inspect and compare the profiles so that the regions are best suited for prismatic joints can be identified. The result of this methodology is the creation of a chain of rigid bodies connected by revolute and prismatic joints that can approximate a set of design profiles

A CLOSED-FORM SOLUTION FOR THE SIMILARITY TRANSFORMATION PARAMETERS OF TWO PLANAR POINT SETS

Image registration covers the set of techniques used in matching images of the same scene. A subset of the image registration problem, identifying the parameters in a similarity transformation, has emerged as useful in a recently defined area of machine design: designing mechanisms for rigid-body shape-change. First, this brief paper shows a potential use for image registration techniques outside the field of machine vision. Second, it presents a closed-form solution for the similarity transformation parameters when the point sets to be matched are restricted to two-dimensional space as is needed in the aforementioned design problem

Physical properties of Liberica coffee (Coffea liberica) berries and beans

Liberica coffee is the most important coffee species grown in Malaysia. However, there is little or no research at all conducted on coffee berries and green coffee beans since the plant itself is a low income crop in Malaysia. Therefore, research on Malaysian Liberica coffee can help to increase the knowledge of coffee farmers and coffee manufacturers in the processing and handling of the coffee. Physical properties of Liberica coffee berries and beans were investigated the current study. The properties investigated include the size, mass, density, coefficient of friction, angle of repose, fracture force and colour. In comparison to Arabica and Robusta coffee, Liberica coffee has the biggest size, mass, true density and fracture force values but were lower in bulk density in both berries and beans. The Liberica berries and beans were found to be orange-ish and yellowish colour respectively. Angle of repose was low and approximately similar in berries and beans while jute fibre gave the highest friction to both Liberica berries and beans

Designing and Building Go-Karts As An Engineering Student Project

This paper describes a semester project carried out by the automotive students within the Faculty of Mechanical Engineering at Kolej Universiti Teknikal Kebangsaan Malaysia (KUTKM)to fulfill the requirement of the Vehicle Dynamics module coursework. The students were required to design and develop their own rally go-kart. This allowed them to apply theoretical knowledge that they have acquired into practical work with their own creativity when designing chassis, suspension system, braking system and steering system. The project essentially had three main parts. Initial study concentrated on the design and analysis of the go-kart using a modern computer aided engineering software, CATIA. The second part of the project is the stage of building the go-kart. Lastly, the final stage was the go-karts had to compete on a racing track. The evaluation of the project was based on the design and analysis of the go-kart using CAD and FEA packages, building process, technical report and also performance during the racing events. The finite element analysis phase of this project is presented here although this is well established in both education and industry. Also described in this paper is the engineering and manufacturing task as well as costing for this project

Effect of raw material variation, process variables and device stability on drying process of rambutan (Nephelium lappaceum L.) seed

This study was conducted to determine the influence of raw material variation, equipment process variables and device stability on the drying process of rambutan seed using oven and microwave drying equipments. The raw material variations studied were skin colour (yellow and fully red), storage period (fresh and stored) and seed mass (5 and 10 g). The important equipment process variables studied were oven temperature (40 and 60°C) and microwave power (250 and 1000 W).The output power and drying distribution in the drying chamber were studied to examine the device stability. Results indicated that the seed mass, oven temperature and microwave power influenced the drying time. The skin colour and storage period were negatively correlated with drying time due to drying time speculate to relay on time required for moisture removal that associated to initial moisture content and seed mass. It is also observed that the drying time will be shorten if the sample was located at the central of the microwave drying chamber. In contrast, the oven exhibited higher stability compared to microwave due to its ability to provide similar level of heating at each location in the drying chamber. This information will aid researchers and industrial operators to design an effective drying process using microwave and oven thus reducing cost and time

The study on performance of naturally aspirated spark ignition engine equipped with waste heat recovery mechanism

The waste heat from exhaust gases represents a significant amount of thermal energy, which has conventionally been used for combined heating and power applications. This paper explores the performance of a naturally aspirated spark ignition engine equipped with waste heat recovery mechanism (WHRM). The amount of heat energy from exhaust is presented and the experimental test results suggest that the concept is thermodynamically feasible and could significantly enhance the system performance depending on the load applied to the engine. However, the existing of WHRM affects the performance of engine by slightly reducing the power

Kinematic synthesis of planar, shape-changing, rigid body mechanisms for design profiles with significant differences in arc length

This paper presents a kinematic procedure to synthesize planar mechanisms capable of approximating a shape change defined by a general set of curves. These “morphing curves,” referred to as design profiles, differ from each other by a combination of displacement in the plane, shape variation, and notable differences in arc length. Where previous rigid-body shape-change work focused on mechanisms composed of rigid links and revolute joints to approximate curves of roughly equal arc length, this work introduces prismatic joints into the mechanisms in order to produce the different desired arc lengths. A method is presented to iteratively search along the profiles for locations that are best suited for prismatic joints. The result of this methodology is the creation of a chain of rigid bodies connected by revolute and prismatic joints that can approximate a set of design profiles

The effect of inner diaphragms and continuous sill selection of automotive B-pillar

This paper discusses in detail on the behaviour of T-frame under specific loading obtained experimentally to investigate the deflection of the vehicle B-pillar. A series of T frame were designed with inner diaphragm at various location in the sill member in order to investigate the effect of inner diaphragm and non-continuous closed hat section in the sill member. These two types of specimens were employed to show the effects of different types of sill member on the stiffness of the overall structure. The finite element analysis and experimental test were carried out on the in-plane bending. The experimental results were compared with the finite element analysis results to demonstrate the effectiveness of the inner diaphragm in the automotive 8-pillar. Based on the results obtained from the experimental work, location of baffles for the specimens do not gives any major influences for in-plane bending case due to the shape and direction baffles are not .suitable. From the results, the specimen with baffles located at the weld line is stiffer than the other specimens

Effect Of Part Features On Dimensional Accuracy Of FDM Model

This research investigates the dimensional accuracy of parts produced using the additive manufacturing method of Fused Deposition Modelling (FDM). The fabrication of parts was carried out based on the standard value of process parameter of Stratasys FDM 400MC machine. Parts with four common features of products in different sizes were fabricated in FDM machines using Acrylonitrile Butadiene Styrene (ABS) material. Then, the linear dimension of each part feature was measured with a Coordinate Measurement Machine (CMM) that was repeated for three times. The accuracy of the fabricated part feature was computed by subtracting the nominal dimension of the part (CAD model)with the measured dimension of FDM model. An analysis of sixteen different dimensions of the part feature was identified that parts dimension had a significant effect on the dimensional accuracy of FDM model. In addition, it was found that FDM machine is less accurate in producing a circular shape part such as cylindrical, sphere and hole as the majority of them are out of the machine’s tolerance

Development of Planar, Shape-changing Rigid Body Segmentation Process for General Design Profiles

This work describes the early segmentation results in the progress of a mechanism design process to produce simple planar machines that could approximate a shape change defined by a set of curves with significant differences in arc length.  The design profiles vary from one another by a combination of rigid-body displacement and shape change that includes significant differences in arc length. Where previous rigid-body shape-change work focused on mechanisms composed of rigid links and revolute joints to approximate curves of roughly equal arc length, this work introduces prismatic joints into the mechanisms in order to produce the different desired arc lengths.  The first step is to convert the design profiles into piecewise linear curves, referred to as target profiles. The piecewise linear representation that proves most useful has points identified along the curve at roughly equal distances. The second step is to compare segments of the target profiles seeking those that are best approximated by a common rigid body and those that share curvature similarities allowing for the introduction of a prismatic joint. In the end, a chain of rigid bodies that are joined by pin and prismatic joints can be produced. The chain can closely estimate the shape of a set of design profiles