In the present study, the AA 2024/AA 7072/AA 2024 MULTILAYER composite was fabricated through an accumulative roll bonding process at 250°C. The resultant mechanical properties were evaluated after different deformation cycles at ambient temperature. It was observed that all layers were uniform and continuous during the first cycle of accumulative roll bonding. Still, after the 4th ARB cycle, AA 7072 layers were gradually necked and separated into small fragments with continuous deformation up to the 6th cycle due to lower formability compared with AA 2024 layers. After the 7th deformation cycle of ARB processing, AA 7072 fragments were distributed non-uniformly in the AA 2024 matrix. In addition, fractography analysis was conducted using scanning electron microscopy (SEM) to observe the microstructure evolution and the fracture mechanism. Also, the mechanical properties were evaluated by tensile testing and micro-hardness measurements. It was observed that hardness and tensile strength improve with increasing accumulative roll bonding cycles. Maximum tensile strength of about 389MPa was obtained after 7 cycles of accumulative roll bonding.

In this research, the influence of thermal cycling on the fracture toughness and maximum load in mode I delamination of polymer matrix COMPOSITES (PMCs) was investigated experimentally and analytically. To eliminate the effect of the remote ply orientation on the fracture toughness during delamination initiation and propagation, double cantilever beam (DCB) specimens with a stacking sequence of [0]16 using unidirectional glass fibers and epoxy resin were considered. The specimens were thermal-cycled between 15°, C and 65°, C for 50-150 cycles. One group of uncycled specimens were tested at the commencement of the investigation as a control group. During the DCB test and receiving universal tensile machine results, the specimens were inspected by 2 real-time cameras to record the delamination length and initial crack tip opening displacement (ICTOD). The strain energy release rate (SERR) approach was used for obtaining the critical fracture toughness (GIC) from the experimental data. By employing the digital image correlation (DIC) method, the initial crack tip separation profile was obtained. The measured bridging laws were used with cohesive elements in ABAQUS commercial software to accurately model the delamination propagation in DCB specimens. Investigation of load variations revealed that critical fracture toughness in mode I of delamination is firmly affected by the thermal fatigue process.

Metallic MULTILAYERs have drawn worldwide attentions in recent years since they exhibit many attractive characteristics in mechanical, electrical and magnetic properties. In this research Cu-Ag MULTILAYER COMPOSITES were produced by accumulative roll bonding (ARB) method. The variation of layer structure during ARB cycles and codeformation of Cu and Ag layer were studied by scaning electron microscopy (SEM). The results showed that the continuity of the constituent layer remained intact until the end of the ninth cycles. During codeformation of layers the copper hard phase necked and the silver soft phase undulated. finally, factors affecting layer continuity and codeformation were investigated.

LEO orbit space radiations in which the protons has the main contribution, have survived devastating effects on electronic components. The damage caused by ionizing protons on the satellite electrical components in the circuit LEO moves was reviewed. By studying the LEO orbit by Shieldose software, the worst-case scenario was evaluated for a satellite. Considering the electronic components based on metal oxide semiconductor (MOS), a design for protection against TID originated from captured protons was done by MULASSIS software based on Monte Carlo calculations. Considering the weight and volume constraints, multiple layers for ionizing dose reduction were studied. Results show that a three-layer combination of shielding materials including low, high and low density materials, which simultaneously optimize the weight and volume, makes the optimum protection.

This paper presents a new wideband, low-loss and sharp rejection Band pass filter which is implemented by using broadside coupled lines and stepped-impedance open circuit stubs. It is demonstrated that using stepped impedance open stub, controllable transmission zeroes are attainable. Transmission line model for proposed structure is introduced and detailed analysis is investigated. The goals of broad pass band and sharp rejection are achieved by choosing the impedances of transmission lines properly. Designed filter operates in 2-6 GHz with low insertion loss (less than 1dB) and high rejection in out of frequency band. The theoretically predicted performance is in good agreement with experimental results.