H. R. Zarei,
Volume 5, Issue 3 (9-2015)
Abstract
This research deals with axial and oblique impact crash tests on simple and hybrid composite tubes. Axial and oblique impact tests have been generated on simple and hybrid composite tubes with one, two and three layers. A drop test rig was used to conduct the experiments. Furthermore, in order to gain more detailed knowledge about the crash process, finite element simulations of the experiments have been performed. The explicit finite element code LS-DYNA was used. The simple tube and the composite hybrid tubes are modeled with thin layer shell elements. The elastic-plastic material model was used for the aluminum tube and the Chang-Chang failure model was implemented for the composite layers. In terms of finding more efficient (higher energy absorption) and lighter crash absorbers particularly, the absorbed energy and specific energy absorption are considered in this research. E SAE
Hamidreza Zarei, Mohammad Nazari,
Volume 12, Issue 3 (9-2022)
Abstract
In this manuscript, the energy absorption behavior of the empty aluminum and ALPORAS foam-filled square tubes is investigated through experimental and numerical routes. The experimental method is conducted by an axial impact test apparatus. To discover more details about crushing behavior, LS DYNA software is used for numerical simulation of the tests. The results of both methods are in satisfactory compliance. As a novelty, the crash performance of tubes filled with different foam densities is investigated. To examine the foam density effect on energy absorption of the tube, multi-layer foams with three different densities have been applied. It has been proven that filling the tubes with gradient foam improves the crash characteristics of the tubes. Numerical results revealed that tubes filled with gradient foam filler can absorb more energy than empty and tubes filled with different individual foams of lower weight. In numerical simulations, the required foam parameters are estimated from existing formulas. Compression test results of foam with different densities are implemented for calibrating these formulas.
Mr. Mohammad Zarei-Jelyani, Mr. Amirhossein Salehi, Dr. Mohsen Babaiee, Dr. Mohammad Mohsen Loghavi,
Volume 14, Issue 2 (6-2024)
Abstract
The global transition towards renewable energy necessitates efficient energy storage solutions to address the intermittency of renewable sources. Lithium-ion batteries (LIBs), widely utilized in electric vehicles (EVs) for their high energy density and efficiency, yet their performance at low temperatures remains a challenge. This study investigates the influence of electrolyte solvent composition on LIB performance under low-temperature conditions. Three electrolytes were studied: a standard electrolyte (STDE) comprising 1 M LiPF6 in ethylene carbonate (EC) and diethyl carbonate (DEC), a low-temperature electrolyte (LTE) consisting of 1 M LiPF6 in EC, ethyl methyl carbonate (EMC), and ethyl acetate (EA), and a long-cycle-life electrolyte (LCLE) containing 1 M LiPF6 in EC/EMC. The EIS results revealed significant differences in resistance values among the electrolytes at varying temperatures. Specifically, at 0 °C, the STDE exhibited a charge transfer resistance (Rct) of 1055.3 Ω and a solid electrolyte interface resistance (RSEI) of 803.4 Ω, whereas the LTE showed a substantially lower Rct of 507.4 Ω and RSEI of 64.2 Ω, indicating superior low-temperature performance. Similarly, at -20 °C, the Rct values for STDE, LTE, and LCLE were 8878.6 Ω, 854.2 Ω, and 15622 Ω, respectively, with corresponding RSEI values of 172.1 Ω, 92.4 Ω, and 2364 Ω. Notably, the addition of EA in the LTE formulation contributed to enhanced low-temperature performance, likely by lowering the overall viscosity of the electrolyte mixture and improving ionic mobility. This study demonstrates the critical role of solvent composition, particularly EA, in optimizing LIB performance for cold climate applications.