Experimental Evaluations on Braking Responses of Magnetorheological Brake

This paper presents experimental evaluations on braking responses of Magnetorheological Brake (MR Brake) at various current and load. The MR brake consists of a rotating disk that immersed with Magnetorheological Fluid (MR Fluid) where the fluid behavior is changing under influence of magnetic fields. The experiments are performed using MR brake test rig to obtain three output responses namely the angular velocity response, torque response and load displacement response. The MR brake generates maximum torque at high current and causes fast decrement of shaft angular velocity. The effectiveness MR brake torque happens at minimum load with low stopping time

Simplified model for the non-linear behaviour representation of reinforced concrete columns under biaxial bending

In the present paper a simplified model is proposed for the force-deformation behaviour of reinforced concrete members under biaxial loading combined with axial force. The starting point for the model development was an existing fixed-length plastic hinge element model that accounts for the non-linear hysteretic behaviour at the element end-sections, characterized by trilinear moment-curvature laws. To take into account the section biaxial behaviour, the existing model was adopted for both orthogonal lateral directions and an interaction function was introduced to couple the hysteretic response of both directions. To calibrate the interaction function it were used numerical results, obtained from fibre models, and experimental results. For the parameters identification, non-linear optimization approaches were adopted, namely: the gradient based methods followed by the genetic, evolutionary and nature-inspired algorithms. Finally, the simplified non-linear model proposed is validated through the analytical simulation of biaxial test results carried out in full-scale reinforced concrete columns

Evaluation on crashworthiness and energy absorption of composite light airplane

[[abstract]]The main aim of this study was to explore the safety differences when using aluminum alloy and three different fiber reinforced composites as material for the cockpit and fuselage of light aircraft under crash landing. In accordance with the cockpit reduction amount stipulated by MIL-STD-1290A in which the reducing rates in all directions cannot exceed 15%, this study established the safety zones of impact speeds and impact angles. The overall safety zones of the carbon fiber reinforced composites and glass fiber reinforced composites cockpits were higher than that of the aluminum alloy cockpit by 38.56% and 32.12%, respectively. Among the four different fuselage materials, when carbon fiber reinforced composites was used as the cockpit material, except that the reducing rate for the crashing in the Y direction was slightly higher than the aluminum alloy cockpit, the reducing rate in the X direction and the inclined beam A direction during crashes were less than other materials, and the safety of its overall cockpit was also the most superior to other materials. The energy absorption capability of the aluminum alloy fuselage was better than the fuselages of all composite materials.[[notice]]補正完

Development and Modification of a Single Overhead Camshaft 4-Valve 4-Stroke 135 cc Formula Varsity Race Car Engine

The engine that was chosen to be developed and modified is Yamaha LC 135 Single Overhead Camshaft (SOHC) 4-valve 4-stroke 135cc liquid-cooled engine. The engine selection is based on the specification, rule and regulation in UTeM Formula Varsity 2012 (FV 2012). The engine performance is determined by engine operating characteristics. The engine air flow affects the filtration, intake and exhaust systems. The heat from the engine rejected to the surrounding through the active cooling system which has radiator and fan. The selection of the engine is based on weighted decision matrix which consists of reliability, operating and maintenance cost, fuel consumption and weight. The score of the matrix is formulated based on relative weighted factor among the selections. It been compared between Yamaha LC 135 Single Overhead Camshaft (SOHC) 4-valve 4-stroke 135cc liquid-cooled engine, Honda Wave 125 X Air Cooled, 4 Cycle Engine Overhead Camshaft (OHC) and Suzuki Shogun RR 4 stroke air cooled Single Overhead Camshaft (SOHC). The modification is applied to the engine through the simulation and tuning of Capacitor Discharge Ignition (CDI)

Development of Formula Varsity Race Car Chassis

Three chassis designs have been developed using commercial computer aided design (CAD) software. The design is based on the specifications of UTeM Formula VarsityTM 2012 (FV2012). The selection of the design is derived from weighted matrix which consists of reliability, cost, time consumption and weight. The score of the matrix is formulated based on relative weighted factor among the selections. All three designs are then fabricated using selected materials available. The actual cost, time consumption and weight of the chassis’s are compared with the theoretical weighted scores. Standard processes of cuttings, fittings and welding are performed in chassis mock up and fabrication. The chassis is later assembled together with suspension systems, steering linkages, brake systems, engine system, and drive shaft systems. Once the chassis is assembled, the studies of driver’s ergonomic and part accessibility are performed. The completion in final fittings and assembly of the race car and its reliability demonstrate an outstanding design for manufacturing (DFM) practices of the chassis

A preliminary mechanical design evaluation of the Wikispeed car: for light-weighting implications

Purpose Road passenger transportation faces a global challenge of reducing environmental pollution and greenhouse gas emissions because of the vehicle weight increases needed to enhance passenger safety and comfort. This paper aims to present a preliminary mechanical design evaluation of the Wikispeed Car (with a focus on body bending, body torsion and body crash) to assess light-weighting implications and improve the vehicle’s environmental performance without compromising safety. Design/methodology/approach For this research, finite element analysis (FEA) was performed to examine the Wikispeed chassis for light-weighting opportunities in three key aspects of the vehicle’s design, namely, for body bending the rockers (or longitudinal tubes), for body torsion (again on the rockers but also the chassis as a whole) and for crash safety – on the frontal crash structure. A two-phase approach was adopted, namely, in phase one, a 3D CAD geometry was generated and in phase, two FEA was generated. The combination of analysis results was used to develop the virtual model using FEA tools, and the model was updated based on the correlation process. Findings The research revealed that changing the specified material Aluminium Alloy 6061-T651 to Magnesium EN-MB10020 allows vehicle mass to be reduced by an estimated 110 kg, thus producing a concomitant 10 per cent improvement in fuel economy. The initial results imply that the current beam design made from magnesium would perform worst during a crash as the force required to buckle the beam is the lowest (between 95.2 kN and 134 kN). Steel has the largest bandwidth of force required for buckling and also requires the largest force for buckling (between 317 kN and 540 kN). Originality/value This is the first study of its kind to compare and contrast between material substitution and its impact upon Wikispeed car safety and performance

Problems modeling the process of manipulation flexible objects in robotics

During manufacturing processes, there are often tasks of manipulating flexible objects with a displaced center of mass. An important issue is the analysis of problems that arise when designing and modeling pneumatic grippers in robotic cells. We established the main directions for solving the problems of manipulating flexible objects with a shifted center of mass for various types of gripper

Comparative Analysis of Mechanical and Water Absorption Properties of Nano/micro-sized Alumina Filler Based Glass-Jute Hybrid Composites

In recent years, the addition of nano and micro size filler material for fabricating composite materials are emerging concept through which mechanical properties of the composite can be enhanced. Filler based hybrid polymer composite materials are substituting metallic materials because of their low specific wear rate, high specific strength modulus, and less water absorption. In current work, nano and micro Al2O3 filler based Glass-Jute hybrid composite have been fabricated to study the mechanical properties like hardness, impact test, specific wear rate, and flexural strength for each type of composite sample. Water absorption analysis is also carried under three different fluid media namely normal water, river water and de-ionized water-based Al2O3 nanofluid. Nano filler enriched composite attributed the higher magnitudes of hardness, impact strength, flexural strength and lower value of specific wear rate and water absorption compared to micro and normal composites. However, a nanofiller based composite is more suitable for automotive, aerospace and ship manufacturing industries

The Effect of Forming Temperature on the Microstructure and Stress Distribution for Lead Babbitt Alloy in Hot Backward Extrusion Process

This study aims to modify the microstructure and mechanical properties of Babbitt alloy (ASTM B23 alloy 13). Two casting techniques were implemented to manufacture the alloy; Gravity Die Casting (GDC) and New Rheocasting (NRC) techniques. The microscope examination shows that the structures contained two phases, α-Pb and cubic shaped intermetallic compound (β-SbSn) in a matrix of ternary phases. GDC structure was a dendrite α-Pb phase, while the equiaxed structure was observed via NRC, with remaining β-SbSn phase as a cubic shape. The manufactured Babbitt alloy by NRC has the best compression and yield strength, while the castings produced by GDC recorded lower properties. Backward extrusion was used to improve the properties of alloy 13 produced by two casting techniques. The backward extrusion were carried in the temperature range of 20-100°C.NRC samples showed the highest mechanical properties under all extruded conditions. The enhanced mechanical properties were mainly attributed to the grain refinement. FEM-simulation code DEFORM 3D was used to investigate the stress distribution in backward extrusion process of billet. Highest effective stress exists in the transition area between bottom and wall of the workpiece (punch corner). At the inner side of the wall, stress is higher than at the outer side of wall. Keywords: lead Babbitt alloy, gravity die casting, new rheocasting, backward extrusion, microstructure, mechanical properties, FEM-simulation