Papers by Keyword: Cyclic Tension-Compression

Abstract: Ni-Ti-based shape memory alloy (SMA) finds extensive applications, yet its high cost presents a challenge. As a cost-effective alternative, Fe and Cu-based SMAs have gained popularity. In this context, the present experimental study conducts tensile and cyclic tests on Ni-Ti, Cu-Al-Ni, and Fe-Mn-Si SMA bars to compare their mechanical behavior and assess their performance regarding stress-strain response, energy dissipation capacity, and residual deformation. The tensile test results show that Ni-Ti and Fe-based SMAs exhibit higher yield and ultimate stress, as well as failure strain, compared to Cu-based SMA. Moreover, cyclic tension-compression test results reveal that Ni-Ti SMA demonstrates a stable hysteresis loop with higher recovery residual strain compared to Cu-based and Fe-based SMAs. These findings underscore the potential of combining Ni-Ti and Fe-based SMAs as a viable alternative material for smart vibration control system design and retrofitting devices, offering higher energy dissipation capacity and larger ductility with good recentering ability.

Abstract: Fatigue properties of mild steel are investigated under cyclic tension-compression and cyclic torsion loading using ultrasonic fatigue testing equipment and cycling frequency of approx. 20 kHz. Both S-N curves show a distinct change of slope at about 107 cycles, and endurance limits determined at 107 and 109 cycles differ by less than their respective standard deviations. Endurance limit shear stress determined for cyclic torsion loading is about 60% of the tension-compression endurance limit stress, and the slopes of the S-N curves are comparable. Non-propagating cracks could be found in specimens, which did not fail within 109 cycles in torsion loading endurance tests. The endurance limit can be understood as maximum stress amplitude, where possibly formed small cracks do not propagate to failure.