Showing 5 results for Tehrani
M.farzin, M. Salmani-Tehrani and S.h. Hashemolhoseini,
Volume 21, Issue 1 (7-2002)
Abstract
In this study, "Buckling Limit of Strain" (B.L.S.) is introduced as one of the most important limiting factors in cold roll forming process. B.L.S. is calculated by the finite element procedure. Then for two particular processes with existing analysis and experimental results, B.L.S. has been determined and evaluated. LUSAS 12.3 is used for finite element analysis. The results show that when buckling of the sheet metal is the limiting factor, B.L.S. is in good agreement with practical limits. It has also been shown that flower pattern can be well predicted when B.L.S. is obtained and this idea is another new outcome from this study. Using this criterion to define and determine B.L.S. and to design the flower pattern is a new concept accomplished for the first time.
Keywords: Cold Roll-Forming, Nonlinear Finite Element Analysis, Local Buckling
M. Tehrani Dehkordi, S. H. Bahrami, R. Nategi Jahromi,
Volume 33, Issue 3 (Journal of Advanced Materials- winter 2015)
Abstract
In this study, the effects of different parameters on charpy impact properties of pure and hybrid composite laminates reinforced with basalt and glass filaments were investigated. For this purpose, five types of basalt and glass laminates with
quasi-isotropic stacking sequence, namely, a pure basalt, a pure glass, two inter-ply hybrid and one intra-ply hybrid composites were produced. Epoxy resin was used as matrix material. After that, the impact test was performed and the average absorbed energy of each type of specimens was determined. The results indicated that the pure basalt and nylon laminates had the highest and least absorbed energy, respectively. The hybrid laminates had the absorbed energy somewhere between the pure basalt and glass ones. Also, between the hybrid composites, the intra-ply laminate had a better impact performance than the inter-ply ones.
M. Tehrani, H. Nosraty, A. Lorak,
Volume 38, Issue 3 (Journal of Advanced Materials-Fall 2019)
Abstract
Due to their sensitivity to impact-induced delamination, woven fabric reinforced polymer composites have limited practical applications. Hybridization of polymer composites has been proposed as a solution to this problem. In this study, the effects of fiber reinforcement type, hybridization method, plies stacking sequence and loading rate on mode I delamination behavior of pure basalt, pure nylon, inter-ply and intra-ply hybrid (basalt/nylon) composites were investigated. Composites were length during its propagation in composite samples was measured by mode I delamination test. The inter-laminar fracture toughness of composite specimens was calculated using modified double-cantilever beam theory and the results were compared by statistical methods. A 30 to 80% improvement in the critical fracture toughness of intra-ply hybrid composite compared to pure ones was recorded. Moreover, the delamination initiation load decreased significantly by increasing the loading rate.
H. Fallah-Arani, S. Baghshahi, A. Sedghi, F. Shahbaz Tehrani,
Volume 40, Issue 2 (Journal of Advanced Materials-Summer 2021)
Abstract
In this research, the influence of titanium dioxide nanoparticles on the structural and magnetic properties of high-temperature superconductor Bi1.6Pb0.4Sr2Ca2Cu3O10+θ (Bi-2223) from the Bi-based ceramic system (BSCCO) was studied. In order to investigate the synthesized samples, X-ray diffractometry and magnetic measurements were performed. Based on the magnetic measurements, the superconductivity transition temperature declined with the increase in the nanoparticles' content. The addition of nanoparticles affected on the hysteresis loop width. Accordingly, the compound containing 0.2 wt.% nanoparticles had the maximum magnetization, hysteresis loop width, and critical current density.
H. Fallah-Arani, N. Riahi-Noori, S. Baghshahi, A. Sedghi, F. Shahbaz Tehrani,
Volume 40, Issue 4 (Journal of Advanced Materials-Winter 2022)
Abstract
In this research, the effect of addition of silicon carbide (SiC) nanoparticles on the improvement of the structural, superconductivity, magnetic, and flux pinning properties of high-temperature superconductor Bi1.6Pb0.4Sr2Ca2Cu3O10+θ (Bi-2223) was investigated. The Bi-2223 ceramic superconductor was prepared using the sol-gel method, and silicon carbide nanoparticles were modified by Azobisisobutyronitrile (AIBN). The X-ray diffractometry, feild emission scanning electron microscopy, magnetic susceptibility, and hystersis loop measurements were performed to characterize the synthesized compounds. Based on the magnetic measurements, the superconductivity transition temperature dropped with an increase in the content of nanoparticles. Also, the maximum magnetization, hysteresis loop width, critical current density, and magnetic flux pinning force belonged to the sample with 0.4 wt.% SiC nanoparticles.
