Fatigue behavior and failure mechanism of basalt FRP composites under long-term cyclic loads

Abstract

This paper studies the fatigue behavior of basalt fiber reinforced epoxy polymer (BFRP) composites and reveals the degradation mechanism of BFRP under different stress levels of cyclic loadings. The BFRP composites were tested under tension-tension fatigue load with different maximum stress levels by an advanced fatigue loading equipment combined with in-situ scanning electron microscopy (SEM). The specimens were under long-term cyclic loads up to 1×10 7 cycles. The stiffness degradation, S-N curves and the residual strength of run-out specimens were recorded during the test. The fatigue strength was predicted with the testing results using reliability methods. Meanwhile, the damage propagation and fracture surface of all specimens were observed and tracked during fatigue loading by an in-situ SEM, based on which damage mechanism under different stress levels was studied. The results show that the prediction of fatigue strength by fitting S-N data up to 2×10 6 cycles is lower than that of the data by 1×10 7 cycles, which reveals that the fatigue strength perdition is highly associated with the long-term run-out cycles and traditional two million run-out cycles cannot accurately predict fatigue behavior. The SEM images reveal that under high level of stress, the critical fiber breaking failure is the dominant damage, while the matrix cracking and interfacial debonding are main damage patterns at the low and

Effect of fatigue loading on stiffness degradation, energy dissipation, and matrix cracking damage of CFRP [±45]3Scomposite laminate

“…The continuous coalescence of matrix cracks in high‐stressed specimen leads to the formation of larger cracks. These cracks were arrested in the fibre‐matrix region causing fibre‐matrix debonding which ultimately causes single ply failure . The fibre‐matrix debonding and single ply failure redistribute the load to remaining plies.…”

“…Vassilopoulos and Philippidis reported a lower stiffness reduction for higher stressed specimens for various off‐axis GFRP laminates. The final failure of the high‐stressed specimen was fibre dominated whereas with comparatively lower stress, it was always matrix dominated . The stiffness degradation is interrelated with residual strength and has been used as a non‐destructive parameter to monitor the remaining life .…”

“…The final failure of the high-stressed specimen was fibre dominated whereas with comparatively lower stress, it was always matrix dominated. [37][38][39][40] The stiffness degradation is interrelated with residual strength and has been used as a non-destructive parameter to monitor the remaining life. 41 Various studies have proposed analytical or theoretical models to correlate transverse cracking and stiffness degradation under fatigue loading.…”

Impact of Frequency of Load Changes in Fatigue Tests on the Temperature of the Modified Polymer

“…During exploitation, means of transport and construction buildings are often exposed to variable impact loads which may cause sudden destruction of the overloaded structure with loads definitely below their static strength [15]. Additionally, in the case of applying adhesive joints in loaded structures, it is necessary to take into consideration their operating temperature, since their considerable disadvantage is low resistance to temperature changes [16].…”

Study on the Effect of Different Fe2O3/ZrO2Ratio on the Properties of Silicate Glass Fibers

“…Compared with ordinary glass fiber, basalt fiber has excellent high tensile strength, elastic modulus, creep resistance, fatigue resistance, high temperature resistance, and other properties [3,4] and is generally considered as a material with excellent alkali resistance [5][6][7][8], which could be widely used in many fields such as civil engineering, transportation, and marine engineering [9,10].…”