scholarly journals Preliminary Evaluation of the Influence of Surface and Tooth Root Damage on the Stress and Strain State of a Planetary Gearbox: An Innovative Hybrid Numerical–Analytical Approach for Further Development of Structural Health Monitoring Models

Computation ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 38
Author(s):  
Franco Concli ◽  
Athanasios Kolios

Wind turbine gearboxes are known to be among the weakest components in the system and the possibility to study and understand the behavior of geared transmissions when subject to several types of faults might be useful to plan maintenance and eventually reduce the costs by preventing further damage. The aim of this work is to develop a high-fidelity numerical model of a single-stage planetary gearbox selected as representative and to evaluate its behavior in the presence of surface fatigue and tooth-root bending damage, i.e., pits and cracks. The planetary gearbox is almost entirely modelled, including shafts, gears as well as bearings with all the rolling elements. Stresses and strains in the most critical areas are analyzed to better evaluate if the presence of such damage can be somehow detected using strain gauges and where to place them to maximize the sensitivity of the measures to the damage. Several simulations with different levels, types and positions of the damage were performed to better understand the mutual relations between the damaged and the stress state. The ability to introduce the effect of the damage in the model of a gearbox represents the first indispensable step of a Structural Health Monitoring (SHM) strategy. The numerical activity was performed taking advantage of an innovative hybrid numerical–analytical approach that ensures a significant reduction of the computational effort. The developed model shows good sensitivity to the presence, type and position of the defects. For the studied configuration, the numerical results show clearly show a relation between the averaged rim stress and the presence of root cracks. Moreover, the presence of surface defects seems to produce local stress peaks (when the defects pass through the contact) in the instantaneous rim stress.

2018 ◽  
Vol 33 (2) ◽  
pp. 236-253 ◽  
Author(s):  
Taimoor A Khan ◽  
Saad Nauman ◽  
Zeeshan Asfar ◽  
M Ali Nasir ◽  
Zaffar M Khan

In this article, we have explored screen printing as a fast and reliable process for the deposition of nanocomposite layer on glass fiber-reinforced plastic (GFRP) substrate for in situ structural health monitoring. The screen-printed sensor comprised of a thermoplastic matrix (high density polystyrene) and a dispersed nanofiller (carbon nanoparticles). Notches of different sizes (2.5 mm and 4.0 mm) were introduced to study the response of sensors to an existing damage. Stress concentrations were plotted across the width and the sensor results were correlated with the simulated stress concentrations to evaluate the response of sensors with respect to local stress concentrations. It was found that the screen-printed sensors responded to the stress concentrations since the layers were deposited in the vicinity of notches. The gauge factors altered due to the presence of notches indicating sensor sensitivity to the preexisting damage and resultant stress concentrations.


Author(s):  
Luis Eduardo Jaramillo Bustamante ◽  
Edison jair Bejarano sepulveda ◽  
Volnei Tita ◽  
Marcelo Leite Ribeiro

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