共查询到3条相似文献,搜索用时 15 毫秒
1.
Dong-Woo Lee Soon-Hyeok Hong Seok-Swoo Cho Won-Sik Joo 《Journal of Mechanical Science and Technology》2005,19(7):1393-1404
Fatigue crack growth and life have been estimated based on established empirical equations. In this paper, an alternative
method using artificial neural network (ANN) -based model developed to predict fatigue damages simultaneously. To learn and
generalize the ANN, fatigue crack growth rate and life data were built up using in-plane bending fatigue test results. Single
fracture mechanical parameter or nondestructive parameter can’t predict fatigue damage accurately but multiple fracture mechanical
parameters or nondestructive parameters can. Existing fatigue damage modeling used this merit but limited real-time damage
monitoring. Therefore, this study shows fatigue damage model using backpropagation neural networks on the basis of X-ray half
breadth ratioB/B
0
, fractal dimensionD
f
and fracture mechanical parameters can estimate fatigue crack growth rateda/dN and cycle ratioN/N
f
at the same time withinengineering limit error (5%). 相似文献
2.
Nonlinear ultrasonic techniques for nondestructive assessment of micro damage in material: A review 总被引:2,自引:0,他引:2
Kyung-Young Jhang 《International Journal of Precision Engineering and Manufacturing》2009,10(1):123-135
The nondestructive assessment of the damage that occurs in components during service plays a key role for condition monitoring
and residual life estimation of in-service components/structures. Ultrasound has been widely utilized for this; however most
of these conventional methods using ultrasonic characteristics in the linear elastic region are only sensitive to gross defects
but much less sensitive to micro-damage. Recently, the nonlinear ultrasonic technique, which uses nonlinear ultrasonic behavior
such as higher-harmonic generation, subharmonic generation, nonlinear resonance, or mixed frequency response, has been studied
as a positive method for overcoming this limitation. In this paper, overall progress in this technique is reviewed with the
brief introduction of basic principle in the application of each nonlinear ultrasonic phenomenon. 相似文献
3.
This paper is concerned to performance improvement of boost PFC converter under large random load fluctuation, ensuring unity power factor (UPF) at source end and regulated voltage at load side. To obtain such performance, a nonlinear controller based on dynamic evolution path theory is designed and its robustness is examined under both heavy and light loading condition. In this paper, %THD and zero-cross-over dead-zone of input current is significantly reduced. Also, very less response time of input current and output voltage to that of load and reference variation is remarked. A simulation model of proposed system is designed and it is realized using dSPACE 1104 signal processor for a 390VDC, 500 W prototype. The relevant experimental and simulation waveforms are presented. 相似文献