Applied Numerical Analysis. By C.F. Gerald. Pp. xii, 340. £3·60. 1970. (Addison-Wesley.)

Weight reduction of vehicle is very important because vehicle weight directly affects energy consumption. Studies researching lightweight vehicle manufacturing process that use polymers are reviewed in this paper. Approaches reducing the weights of vehicles using polymers most frequently involve replacing ferrous and non-ferrous metals with polymers and increasing the specific strengths and rigidities of polymers. Researches into polymers for use in lightweight vehicle are classified into high performance polymers, polymers for weight reduction, reinforced polymer composites, polymer sandwich panels, and polymer/metal hybrid systems. A diverse range of polymer materials can be used to make vehicle components and the manufacturing methods required to produce and work those materials vary greatly. Shaping processes must be chosen according to the materials being used and the product design. Replacement of metal products with polymer materials in current vehicles is limited. Large amounts of lightweight materials, such as polymers, will be greatly used to construct newly developed vehicles, including electric and electric/hybrid vehicles.

Research trends in polymer materials for use in lightweight vehicles

Design optimization and manufacture of hybrid glass/carbon fiber reinforced composite bumper beam for automobile vehicle

The near-dry wire-cut electrical discharge machining (WEDM) process is an environment-friendly manufacturing process, in which there is no harmful effect to the operators. The authors focus on the non-polluting ways to cut the materials and to meet the technical requirements like high material removal rate (MRR) and low surface roughness (Ra). In the near-dry WEDM, the finite discrete periodic series sparks between the wire electrode and conducting work material separated by minimum quantity of deionized water mixed with compressed air (air-mist) as a dielectric medium. In the present research, parametric analysis of the process has been performed with the molybdenum wire tool and high speed steel (HSS-M2) work piece. Experiments have been performed using air-mist as the dielectric medium to study the impact of gap voltage, pulse-on time, pulse-off time, air-mist pressure and discharge current on the MRR and Ra using the mixed orthogonal (L18) array-Taguchi method. Taguchi based analysis of variance test was performed to identify the significant parameters. The gap voltage, pulse-on time, discharge current and air-mist pressure were found to have momentous effects on MRR and Ra. The best regression models for MRR and Ra have been developed by regression analysis. The optimal rough and finish cutting parameters have been predicted by Pareto-front using the multi-objective evolutionary algorithm (MOEA).

Experimental investigation and parameter optimization of near-dry wire-cut electrical discharge machining using multi-objective evolutionary algorithm

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High Strength Ductile Aluminium Matrix Composite

The purpose of this study was to design a light-weight sandwich panel for trailers. Strength calculations and selection of different materials were carried out in order to find a new solution for this specific application. The sandwich materials were fabricated using vacuum infusion technology. The different types of sandwich composite panels were tested in 4-point bending conditions according to ASTM C393/C393M. Virtual testing was performed by use of ANSYS software to simplify the core material selection process and to design the layers. 2D Finite element analysis (FEA) of 4-point bending was made with ANSYS APDL (Classic) software. Data for the FEA was obtained from the tensile tests of glass fiber plastic (GFRP) laminates. Virtual 2D results were compared with real 4-point bending tests. 3D FEA was applied to virtually test the selected sandwich structure in real working conditions. Based on FEA results the Pareto optimality concept has been applied and optimal solutions determined.

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Design and Testing of Sandwich Structures with Different Core Materials

This paper focuses on the analysis of mechanical vibrations caused by different eccentricities in the rotor of a slow-speed slotless permanent magnet generator. The analysis of different eccentricities and their influences was carried out on a full scale laboratory test machine. Three most common mass center dislocation faults of a generator rotor that can occur in the production phase of the machine were investigated: asymmetrical rotor weight distribution, none coaxiality of rotor and stator, dislocated rotor. The analysis was conducted to obtain information on how different eccentricities influence vibrations and how to take this into account in production. Mentioned cases were chosen as they represent most common eccentricity faults caused by mistakes in production and assembly. Vibration measurements were carried out by non-contact optical measurement system. The measurement procedure and process are described in the paper as they are a crucial part of the analysis. The obtained results show that additional mechanical vibrations depend on the relation between eccentricity types. In addition, it was identified that rotor rotational speed affects the vibration amplitudes only slightly and the rate of influence is also dependent on the eccentricity type. Dynamic eccentricity was found to be the most dangerous case compared to the others.

Analysis of mechanical vibrations caused by eccentricity in a slow-speed slotless permanent magnet generator

This paper presents a novel design optimization procedure for an ultra large diameter permanent magnet generator. As the machine features unorthodox electromagnetic and mechanical layouts, basic principles for determining structural loads together with material quantities for cost estimation are described. Finite element modelling with beam elements is used for retrieving stresses and deformations of the novel carrier structure. Mathematical system response model of the generator is created with artificial neural networks, while genetic algorithm with gradient method is utilized for determining the optimal solutions. Input dataset for the model build-up is constructed with a help of a full factorial experimental method. Achieved results are utilized for describing the relationship between the structural response and efficiency values of the generator. As the design of the machine has to fulfil contradicting technical and economical requirements, Pareto optimality concept is employed. As an example, a set of optimal solutions is determined for the particular case. DOI: http://dx.doi.org/10.5755/j01.eee.21.3.10278

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Papers

Design and Testing of Sandwich Structures with Different Core Materials

Analysis of mechanical vibrations caused by eccentricity in a slow-speed slotless permanent magnet generator

Multi-Criteria Design Optimization of Ultra Large Diameter Permanent Magnet Generator

Optimal Design of Slotless Permanent Magnet Generators