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Showing 3 results for Hasanzadeh

R. Hasanzadeh, T. Azdast, R. Eungkee Lee, A. Afsari Ghazi,
Volume 14, Issue 3 (September 2017)

Material selection is a main purpose in design process and plays an important role in desired performance of the products for diverse engineering applications. In order to solve material selection problem, multi criteria decision making (MCDM) methods can be used as an applicable tool. Bumper beam is one of the most important components of bumper system in absorbing energy. Therefore, selecting the best material that has the highest degree of satisfaction is necessary. In the present study, six polymeric nanocomposite materials were injection molded and considered as material alternatives. Criteria weighting was carried out through analytical hierarchy process (AHP) and Entropy methods. Selecting the most appropriate material was applied using technique for order preference by similarity to ideal solution (TOPSIS) and the multi-objective optimization on the basis of ratio analysis (MOORA) methods respect to the considered criteria. Criteria weighting results illustrated that impact and tensile strengths are the most important criteria using AHP and Entropy methods, respectively. Results of ranking alternatives indicated that polycarbonate containing 0.5 wt% nano Al2O3 is the most appropriate material for automotive bumper beam due to its high impact and tensile strengths in addition to its low cost of raw material. Also, the sensitivity analysis was performed to verify the selection criteria and the results as well.

M. Abbasalizadeh, R. Hasanzadeh, Z. Mohamadian, T. Azdast, M. Rostami,
Volume 15, Issue 4 (December 2018)

Shrinkage is one of the most important defects of injection molded plastic parts. Injection molding processing parameters have a significant effect on shrinkage of the produced parts. In the present study, the effect of different injection parameters on volumetric shrinkage of two polymers (high-density polyethylene (HDPE) semi-crystalline thermoplastics and polycarbonate (PC) as a representative of amorphous thermoplastics) was studied. Samples under different processing conditions according to a L27 orthogonal array of Taguchi experimental design approach were injected. Effect of material crystallinity on the shrinkage of injected samples was investigated. Obtained results revealed that semi-crystalline thermoplastics have larger shrinkage values in comparison with amorphous thermoplastics. Shrinkages of injected samples were also studied along and across the flow directions. Results showed that the flow path can dramatically affect the shrinkage of semi-crystalline thermoplastics. However for amorphous thermoplastics, results showed an independency of obtained shrinkage to flow direction. Analysis of variance (ANOVA) results illustrated that cooling time was the most effective parameter on shrinkage for both PE and PC injected samples; followed by injection temperature as the second important parameter. The optimum conditions to minimize shrinkage of injection molded samples are also achieved using signal to noise ratio (S/N) analysis.
R. Hasanzadeh, S. Fathi, T. Azdast, M. Rostami,
Volume 17, Issue 0 (1-2020)

Heat transfer in foams consists of conduction through solid and gaseous phases, convection within the cells as well as radiation through the whole medium. Radiation thermal conduction affects the overall thermal conductivity by 40% in a high porosity. Therefore, the investigation of that term seems to be necessary. Radiation thermal conduction depends on the extinction coefficient which its determination is experimentally complex. In this study, this coefficient is theoretically estimated using Glicksman model for polyolefin foams and is verified in comparison with the experimental data. Extinction coefficient which plays an effective role in the radiation thermal conduction depends on the morphological properties including foam and solid densities, cell and strut diameters. The results demonstrate that the radiation thermal conduction decreases by reducing cell size and increasing foam density and strut diameter. An L25 orthogonal array of Taguchi approach is used for optimization of radiation thermal conduction respect to foam density, cell and strut diameters as variable parameters. The analysis of variance results illuminate that foam density and cell diameter with 58 and 32% contribution are the most effective parameters on the radiation thermal conduction, respectively. At optimum conditions according to the prediction tool of Taguchi approach, the radiation thermal conduction significantly decreases to 1.0908 mW/mK.

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