Papers by Keyword: Premature Failure

Abstract: The structural integrity of Pelton runners, crucial in hydroelectric power generation, is severely compromised by suboptimal repair practices, leading to premature failures and significant operational losses. This study presents a comprehensive analysis of five Latin American case studies (Colombia, Perú and Guatemala), revealing a direct correlation between uncontrolled residual stress and accelerated component degradation. This study demonstrates the effectiveness of integrating XRD with other Non-Destructive Testing (NDT) techniques, enabling the development of predictive models for crack propagation and the optimization of repair protocols. In addition, the results provide evidence that Pelton wheels repair transcends conventional welding, necessitating a profound understanding of residual stress distribution. Precise XRD-driven residual stress determination, pre-and post-intervention, is pivotal for implementing corrective thermal treatments and extending component lifespan. This study demonstrates that integrating XRD into maintenance protocols for Pelton runners constitutes a paradigm shift in structural integrity management. This innovative approach, by enabling precise residual stress analysis, minimizes catastrophic failures and maximizes operational efficiency within hydroelectric power generation. The findings validate the hypothesis that XRD-driven maintenance strategies significantly enhance component longevity and reliability, thereby revolutionizing industry standards.

Abstract: All electrical motor or generator bearings can potential suffers from electric erosion. Unfortunately, problems can start after just a few months of running a new electric motor or generator. From visual inspection, it was found that the failure happened on the raceway surface in equal spacing. There may be many reasons for this – heavier loading than has been anticipated, inadequate or unsuitable lubrication, careless handling, ineffective sealing, or fits that are too tight, with resultant insufficient internal bearing clearance. Each of these factors produces its own particular type of damage and leaves its own special imprint on the bearing. Consequently, by examining a damaged bearing such as visual inspection, it is possible, in the majority of cases, to form an opinion on the cause of the damage and to take the requisite action to prevent a recurrence.

Abstract: Various types and forms of FRP materials have been applied for structural strengthening of reinforced concrete (RC) beams. When CFRP plates are used, however, a premature failure used to occur before strengthening effect appears adequately. This is primarily due to the rip-off of CFRP plate attached on RC beams. Despite of numerous studies on the rip-off failure of externally strengthened RC beams, the failure mechanism is not clearly explained yet. Investigations from the literatures have shown that the rip-off failure is dependant on vertical and shear stresses at the level of main reinforcements in RC beams. This study suggests an analytical model to investigate the ripoff failure load based on the stresses at the level of main reinforcements. The proposed model is relatively simple and produces very comparable results to the test data. Therefore, it is anticipated that the proposed model can be successfully used to provide further information on the rip-off failure mechanisms and its prevention.