Journal of Materials and Engineering Structures

65-78

Authors: Sonia Chutani, Jagbir Singh

In this paper, the use of extended versions of basic particle swarm optimization (PSO) namely constriction factor PSO, democratic PSO and probabilistic PSO have been presented for optimal design of reinforced concrete (RC) structural elements. The design and optimization procedure follows specifications of Indian codes. Driving idea for carrying out this work was to explore extended versions of PSO for their capabilities to maximize ‘exploration area’ and minimize ‘exploration time’. These algorithms are thereby employed to study their effect on minimizing the cost of RC structural members. Optimal cross-sectional size and reinforcement for the members have been obtained by the use of computer aided environment, whereby whole process of design and optimization has been coded in C++. The design variables have been considered as continuous functions and rounded off appropriately to imbibe practical relevance to the present study. The effectiveness of these algorithms was also tested using certain benchmark functions. Various test cases of beams and columns were considered to confirm the results, and they all indicated good capabilities of these extended algorithms in terms of exploration, convergence behaviour and time. The results were also compared amongst themselves to understand adaptability of an algorithm under specific conditions.

87-97

Authors: Ahmed HAKEM, Youcef BOUAFIA, Farid ASMA

The objective of this work is to determine the impact of the temper heat treatment (150, 160, 170, 180, 190, 200,220 and 240) °C on the evolution of the main elastic and structural properties of the alloy foundry AlSi7Zn3Cu2Mg (42500). This alloy will be subjected to precipitation hardening. This is one of the most successful methods to considerably improve the mechanical properties of the alloy, this allows choosing the compromise of high resistances while maintaining satisfactory ductility. The mechanical properties are governed by the combination of four factors: heat treatments, molding process, chemical composition and the shape of the specimen used. We used mainly four techniques namely: The ultrasonic method for the determination of the elastic characteristics, the Brinell hardness HB and the micro hardness Hv to identify the stress field, the Kcv resilience to provides information on fracture mode, brittleness and the impact resistance, and finally to completely identify the alloy, it will be followed by its metallography, microstructure and fracture surface in resilience. The purpose of this work is to study the structural hardening of the alloy AlSi7Zn3Cu2Mg (42500) by considering ten states: crude of casting noted: F taken as reference state. To improve the mechanical characteristics obtained from the crude of castingstate, a structural hardening heat treatment is carried out, the addition of magnesium is necessary in order to make the alloy sensitive to this specific heat treatment T46.