Life estimation model of a cantilevered beam subjected to complex random vibration

Paulus, Mark; Dasgupta, Abhijit; Habtour, Ed

doi:10.1111/j.1460-2695.2012.01693.x

Cited by 18 publications

(30 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For structures subjected to random vibration, Ungar and others [9,12] have proposed that the pseudo velocity is proportional to stress. This applies to numerous geometries, including cantilevered beams.…”

Section: Theorymentioning

confidence: 98%

“…Although natural frequency shifting is a well documented phenomenon, the associated changing stress state is not. To this end a model was developed by Paulus et al [9] where the natural frequency shift and changing stress state were modeled. Time-to-failure (TTF) and natural frequency change were computed for complex random vibration environments using the input Power Spectral Density (PSD), damping and Linear Elastic Fracture Mechanics (LEFM).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Semi-empirical life model of a cantilevered beam subject to random vibration

Paulus

Dasgupta

2012

International Journal of Fatigue

View full text Add to dashboard Cite

Section: Theorymentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Semi-empirical life model of a cantilevered beam subject to random vibration

Paulus

Dasgupta

2012

International Journal of Fatigue

View full text Add to dashboard Cite

“…The presence of cracks in a structure is usually detected by adopting a linear approach through the monitoring of changes in the structure's dynamic response features [27][28][29]. Several studies have reported analytical and experimental results for vibration of cracked Euler-Bernoulli beams and the effects of surface cracks on fundamental frequencies and vibration modes of beams [30][31][32]. Few researchers uncovered nonlinear dynamic behavior of beam structures with single crack in the time history and frequency spectrum [33][34][35].…”

Section: Nonlinear Dynamics Of Undamaged and Damaged Structuresmentioning

confidence: 99%

Detection of fatigue damage precursor using a nonlinear vibration approach

Habtour

Cole

Riddick

et al. 2016

Struct. Control Health Monit.

Self Cite

View full text Add to dashboard Cite

SUMMARYA nonlinear dynamic methodology is developed for detecting and estimating fatigue damage precursor in isotropic metal structures, prior to fatigue crack initiation, based on measurement of changes in the structure nonlinear response to harmonic base excitation. As an example, a damage precursor feature was extracted for cantilever beams by quantifying the reduction in the nonlinear stiffness because of localized microscopic material softening. The nonlinear dynamic analytical model parametrically tracks changes in the nonlinear structural stiffening as a function of the structural response and the loading cycles. Experimental results are obtained by exciting the base of cantilever beams at various amplitude levels. At high response amplitudes, the beams experience three competing simultaneous nonlinear dynamic mechanisms: (i) stiffening because of high response amplitude at the fundamental mode; (ii) softening because of inertial forces; and (iii) softening because of localized microscopic material damage caused by cyclic micro-plasticity. The third mechanism-a potential precursor to fatigue crack initiation in the structure-resulted in a cumulative softening because of early accumulation of cyclic fatigue damage and is the focus of this study. The loading intensity and the number of cycles influenced the relative contribution of these dynamic mechanisms. Nanoindentation studies near the beam clamped boundary were conducted to confirm the fatigue degradation in the local mechanical properties as a function of loading cycles. The proposed detection method is simple to implement and detects the presence of damage precursors but lacks the resolution to discern spatial distributions of the damage intensity. Based on prior knowledge of the structural dynamic characteristics of the beam and using the proposed methodology, damage level and stiffness reduction can be detected and estimated based on changes in the nonlinear structural response. The nonlinear stiffness term in the equation of motion is found to be very sensitive to the proposed fatigue damage precursor, making it an effective method for monitoring structural degradation prior to crack developments. The proposed methodology provides new insights and constitutes a significant step toward the development of new inspection techniques.

show abstract

“…No more precisions are given on the used fixture as in Hammami et al. [8], Paulus et al [9] or Li et al [10]. Only pictures of the experiments show the fixture used.…”

Section: Introductionmentioning

confidence: 99%

Development of a test bench for vibratory fatigue experiments of a cantilever beam with an electrodynamic shaker

et al. 2018

View full text Add to dashboard Cite

Abstract. When fatigue tests are carried out using a shaker, dynamic phenomena often appear and lead to a non-linear behaviour in the experiment. In this paper, the dynamic response of the specimen is studied in order to evaluate the impact on the results. The experiment consists in a notched beam fixed on the armature of an electro-dynamic shaker. The transfer function between the center of the armature and the tip of the beam is obtained with a swept sine near the first resonance frequency of the specimen. The drive is a constant acceleration amplitude. An evolution in the transfer function of the beam is observed when the drive is modified: the resonance frequency decreases and the damping increases. This non-linearity is investigated by studying the movement of the shaker, the fixture and the beam. The results show that the beam close to its resonance disrupt the imposed movement. An experimental setup correcting those defects is proposed.

show abstract

Life estimation model of a cantilevered beam subjected to complex random vibration

Cited by 18 publications

References 13 publications

Semi-empirical life model of a cantilevered beam subject to random vibration

Semi-empirical life model of a cantilevered beam subject to random vibration

Detection of fatigue damage precursor using a nonlinear vibration approach

Development of a test bench for vibratory fatigue experiments of a cantilever beam with an electrodynamic shaker

Contact Info

Product

Resources

About