Integrated component monitoring of highly loaded hybrid porous components

The Collaborative Research Centre TRR 375 aims to establish and conduct fundamental research into multifunctional, high-performance components made of hybrid, porous, metallic materials with locally graded properties (HyPo), which are produced using additive manufacturing techniques. The aim is to optimise weight, performance and resource efficiency. However, it is difficult to predict service life and safety because the influence of residual stresses and subsurface properties on fatigue in HyPo components is not well understood. Currently, available monitoring mostly takes place offline or only at the surface, and there is a lack of condition data over the entire life cycle. Furthermore, there is a lack of understanding of the relationship between operational loads and stress relaxation. In sectors such as aerospace, energy, automotive, and tool and machine building, this results in high levels of qualification, downtime, and risk. What is needed are robust, integrated measurement and analysis systems for quality assurance and predictive maintenance, based on knowledge of residual stress relaxation.

Objectives

The objective of subproject A04 is to enable the intelligent, life-cycle-wide monitoring of the condition of highly loaded HyPo components. Using polymer-free, metal-foil-based strain and temperature sensors (provided by project partner IMPT) and machine learning, the remaining service life will be predicted. For graded/porous, multi-material HyPo components, the relationships between residual stresses and subsurface properties will be used to develop inverse models of stress relaxation under long-term loading. This will enable the broader adoption of HyPo components by increasing their reliability and facilitating predictive maintenance, as well as advancing functionalisation and lightweight design.

Benefits

• Knowledge of subsurface properties – beneficial compressive residual stresses, hardness and surface roughness in graded hybrid components.
• Increased service life – Subsurface properties that prevent failure

Approach

The project is embedded within the CRC (TRR 375) at the RPTU Kaiserslautern and Leibniz University Hannover. IFW and IMPT are working closely together. At IFW, XRD-based methods for measuring and modelling residual stresses in HyPo components are being developed. At IMPT, strain/temperature sensor technology based on metal foils and free of polymers is being designed and integrated with minimal impact on the component. The initial focus is on the additive laser-directed energy deposition (L-DED) process with in-situ monitoring. Building on this, machine learning (ML)-based predictions and transfer to other additive processes will follow.

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Contact Patricia Weßel via email at wessel@ifw.uni-hannover.de or by phone at +49 511 762 18295.