- #CANTILEVER IN RAPID SKETCH CRACKED#
- #CANTILEVER IN RAPID SKETCH FULL#
- #CANTILEVER IN RAPID SKETCH CRACK#
used the finite element analysis to study the dynamic behavior of cantilever crack under harmonic loads, where fatigue crack was simulated by transient breathing crack model, and higher order frequency response function was applied for the analyzing nonlinear characteristics.
#CANTILEVER IN RAPID SKETCH CRACKED#
Sundermeye and Weave also used a bilinear spring-mass oscillator system to study the weak nonlinear vibration characteristics of cracked beam, and identified the crack location, crack depth and crack opening load based on corresponding vibration characteristics.
Shen and Chu conducted comparative researches for depicting dynamic response due to crack by virtue of a breathing crack model and a bilinear spring-mass oscillator. The breathing crack model is in accord with an actual fatigue crack by considering nonlinear dynamic characteristics during the crack opens-closes process.
#CANTILEVER IN RAPID SKETCH FULL#
Gudmundson compared the natural frequencies of cracked structure by experimental test to calculation by the full open crack model, the results indicated that the open crack model will lead to lower assess the extent of damage to the structure. Actually, it is a cyclical opened-closed state with a strong nonlinear process. However, a fatigue crack is not generally opening state. For simplicity, most scholars usually used a full open crack model to study the dynamic response of cracked structure ignoring nonlinear effects of fatigue crack. There are two types of crack model, full open crack model and breathing crack model, are assumed that apply for vibration analysis and crack identification.
Therefore, vibration analysis and crack identification for a cracked structure have been received extensive attention, including theoretical study, numerical simulation and experimental test. The emergence and propagation of the crack in structural components arise from long-term fatigue, which influence on the safety and reliability of structure at some extent. Keywords: cracked beam, finite element, contact pairs, sub-harmonics, super-harmonics. Meanwhile, the strategy of experimental validation to the FEM results is discussed. The research results demonstrate that there is obvious nonlinear dynamic behavior for plane beam with a fatigue crack, and the different feature of frequency spectrum can be used to identify the beam damage in structure. Relative amplitude of frequency spectrum with respect to different factors is analyzed to realize sub-harmonics or super-harmonics of cracked beam. Based on the proposed finite element contact model, the influence of excitation frequency, crack depth and crack position on nonlinear dynamic characteristics are discussed in detail. The quarter-point element is used to describe the crack tip singularity. A crack opens and closes during vibration that is simulated as a frictionless plane contact problem, and a finite element contact model for a cantilever cracked beam is established. The nonlinear dynamic characteristics of plane cracked beam subjected to a harmonic load at the tip are researched.