Mohammad Ali Maghsoudlou, Reza Barbaz Isfahani, Saeed Saber-Samandari, Mojtaba Sadighi,
Volume 18, Issue 2 (June 2021)
Abstract
The low velocity impact (LVI) response of pure and glass fiber reinforced polymer composites (GFRP) with 0.1, 0.3 and 0.5 wt% of functionalized single-walled carbon nanotubes (SWCNTs) was experimentally investigated. LS-DYNA simulation was used to model the impact test of pure and incorporated GFRP with 0.3 wt% of SWCNT in order to compare experimental and numerical results of LVI tests. All tests were performed in two different levels of energy. In 30J energy, the specimen containing 0.5 wt% SWCNT was completely destructed. The results showed that the incorporated GFRP with 0.3 wt% SWCNT has the highest energy absorption and the back-face damage area of this sample was smaller than other specimens. TEM images from specimens were also analyzed and showed the incorporation of well-dispersed 0.1 and 0.3 wt% of SWCNT, while in specimens containing 0.5 wt% of CNT, tubes tended to be agglomerated which caused a drop in LVI response of the specimen. The contact time of impactor in numerical and experimental results was approximately equal; however, the maximum contact forces in LS DYNA simulation results were higher than the experimental results which could be due to the fact that in the numerical modeling, properties are considered ideal, unlike in experimental conditions.
Morteza Hadi, Omid Bayat, Hadi Karimi, Mohsen Sadeghi, Taghi Isfahani,
Volume 19, Issue 1 (March 2022)
Abstract
In this research, the effect of initial microstructure and solution treatment on rollability and crystallographic texture of a Cu-Mn-Ni-Sn alloy has been investigated. The initial tests indicated that the rolling of the alloy at different temperature conditions is not possible due to formation of second phases. Herein to eliminate the segregated phases, according to DTA analysis, proper temperature for solution treatment was selected as 750°C applied at different periods of time. The obtained results showed that after 15-hour solution treatment, the complete elimination of Sn, Mn, Ni, and Fe-rich phases can be achieved. Also, the peaks of XRD shifted to the higher angles indicating that the alloying elements are dissolved. Meanwhile, the intensity of the texture reduced and the dominant texture changed from Goss and Brass-texture to Copper-texture. Accordingly, the amount of maximum total reduction at the rolling process increased from 16.37 to 109.46 after solution treatment.
