Mehdi Jafari Vardanjani

Vibrational stress relief (VSR) treatment is a method of stress relief which is currently used for different alloys in different sizes. Since the effect of VSR has not been fully analyzed and compared versus thermal stress relief (TSR) process, its merits require wider investigations. In this paper VSR treatment has been performed with certain parameters to check and assure the advantages of the process in terms of mechanical and metallurgical improvements on AISI 1008 workpiece as a preparatory process. The chosen parameters consist frequency, time, and amplitude of vibration. Factorial design of the experiment using response surface methodology has been performed to obtain an optimal response in numerical and experimental tests. The testing coupons have been evaluated in terms of hardness, tensile strength, elasticity modulus, toughness, elongation before fracture, and micro-structure. Experimental results have been compared with finite element analysis (FEA) results and previous studies. FEA elastic-plastic model was used to extract mechanical properties, while hardening effect has been accounted for in the model. The study has demonstrated the influential performance of VSR on the mechanical properties of the samples i.e., yield strength, toughness, elongation, and elasticity modulus while hardness and microstructure have not been affected significantly.

Vibrational stress relief (VSR) treatment as a method of stress relief is currently performed on different alloys and sizes as an appropriate alternative for thermal stress relief (TSR) method. Although many studies have been performed to extend the knowledge about this process, analytical studies in the field of VSR process seems to require wider efforts to introduce the concept more clearly and extensively. In this study, a theoretical model is proposed based on an analytical equation. The proposed equation was modified in terms of required variables including frequency, amplitude, and vibration duration to encompass more practical parameters compared to the previous models. Thus, essential VSR parameters including the number of cycles as a representative of treatment duration, strain rate as a representative of frequency, and the amplitude were embedded in the model to make it comprehensively practical. Experimental tests were also performed and residual stress distribution was measured by X-ray diffractometry (XRD) method for certain points to compare the experimental results with the theoretical output. An acceptable range of conformation was observed between theoretical and experimental results.

Since new towns are to meet the needs of the metropolitan population, it is required to acquaint the populations with the new scientific-technical methods and take one more step towards civilisation. Given that the New Town seeks to provide the latest facilities for citizens, a human-oriented approach can be proposed. New Urbanism with a humanistic approach requires coherent and dynamic planning. New structures and the various needs of the New Towns require comprehensive and integrated planning to utilise recent facilities to lead New Towns toward a human-centred attitude. Therefore, the main purpose of this study is to analyse the key factors affecting the planning of New Towns with a humanistic approach. The method in this research is a descriptive-analytical survey. In the first step of the research, a list of primary factors involved in planning new cities was identified as research variables, using documentary sources and previous research. Then the research variables were analysed based on the Delphi method. Accordingly, 34 variables were provided in five domains for 50 experts in urban planning issues in the form of questionnaires to be analysed in matrices. The findings of the study are demonstrated in five aspects: cultural-social, physical-spatial, economic, environmental, and governance topics, with 34 components. The results show that citizenship rights, social capital, transparency, accountability, law, participation, consensus, quality of performance and managerial effectiveness, efficiency, economic welfare, sustainable active economy, meeting economic needs, quality of texture, and spirituality have the highest impact and the lowest affectedness on the realisation of human-centred New Urbanism. The results can be useful and effective by establishing integrity and fundamental theoretical principles in planning, implementation and strategic control of New Towns.