Can LPTi's XactLIFE system be used to conduct root cause analysis (RCA) of engine component failures?
Yes. The XactLIFE system analyzes the effects of actual engine operating conditions such as rotational speed, time at a given speed at altitude, ambient operating conditions, etc. on the damage accumulation rates in individual engine components using microstructure based damage models. Furthermore, the system automatically computes the influence of individual or combined damage mechanisms on component fracture critical location and life. These features enable speedy computation of the crack nucleation and propagation life under numerous loading and damage mechanisms to effectively identify the root cause of failures.
Can XactLIFE quantify the influence of changes in engine operating environment on the durability of engine components?
Yes. The engine operating and ambient conditions during actual usage is an input to the XactLIFE system. The thermodynamic engine model along with CFD and finite element analysis enables the prediction of the metal temperature and stress-strain states over critical parts for each usage condition. Hence, the crack nucleation sites and propagation lives of durability critical components is computed as a function of the actual usage. In addition the risk of missing a crack can be quantified up front using probabilistic life analyses.
Why is XactLIFE based remaining life prediction more accurate than present life prediction methods?
OEM preventive maintenance recommendations, which are purposely conservative and very costly to turbine owners, often replace components without structural failures and are reluctant to extend life. XactLIFE uses actual usage to predict component/engine/fleet life and reliability, suggest life extension and predictive maintenance strategies for potential savings of 40%. Sensor-based diagnostics and qualitative approaches (like metallurgical testing and NDI) require difficult to get failure data and are inconclusive for long-term predictions. XactLIFE utilizes the actual usage and physics based models for accurate simulation of the engine performance and life prediction.
Can the XactLIFE system be used to assess the impact of engine component design modifications on life improvement?
Yes. The XactLIFE system can be employed as a component design assessment tool for the purpose of improving component durability and life. The system can easily re-evaluate the fracture critical location and life of a component as a function of design modifications such as changes in the design of cooling passages, component material and microstructure, gas path component wall thickness, changing a protective coating, etc.. Some of these modifications are known to result in a change in the component temperature profiles and subsequently the component thermal load during service that eventually affects the component life. The impact of any component level design change can be assessed very easily and quickly using this system. This directly helps in certification for design changes using "Qualification Through Analysis" procedures and reduces the requirement of expensive testing.
Can the XactLIFE system be used to suggest component level design modifications for life extension purposes?
Yes, the XactLIFE system can be used to suggest component level design changes for life extension purposes. Design modification may be considered with respect to component geometric features, material selection including its microstructural state, as well as off design engine working conditions. The system can be used to improve component level design to improve their safe life and damage tolerance under creep, fatigue and combined loading conditions. LPTi possesses component design modification experience for improving low cycle fatigue and high cycle fatigue design margins, component vibration response and creep life in land based as well as aero engine operating environments.
Can XactLIFE be used to assess the impact of repairs and refurbishment treatments on the usable life of engine components?
Yes. Repair and refurbishment processeschange the microstructure of the component. Since the XactLIFE system uses microstructural damage models for conducting life prediction analysis, the system can be effectively used to quantify the effect of any changes in the microstructure of repaired or refurbished components on their residual life.
Can the XactLIFE system help with the life cycle management of aging engines?
Yes. LPTi has developed a unique life cycle management capability for aging engines called "Prognostics Based Overhaul". In this methodology, all Class A components such as discs, spacers and shafts of aging engines are maintained following ENSIP: MIL-HDBK-1783B. Using XactLIFE, the safe inspection interval in conjunction with appropriate guidelines for implementing different non-destructive inspection techniques are provided forthe depot level inspection. The XactLIFE system is further used to assess the remaining life of gas path components and quantify risks associated with any life extension scheme. The requirements and possibility of implementing life extension schemes such as rejuvenation, recoating or repair technologies for the gas path components can be evaluated. This methodology was implemented on a fleet of 43 W101 engines and the customer has used the engines for over 15 years beyond the OEM specified design life limit. The depot level overhaul also reduced the engine overhaul costs by close to 50%.