PSI - Issue 53

Rainer Wagener et al. / Procedia Structural Integrity 53 (2024) 161–171 Author name / Structural Integrity Procedia 00 (2019) 000–000

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Fig. 6: Analyzing the surface profile, schematically.

In Fig. 7 the cumulative frequency of K R values for three different walls are shown. The spectra shown summarize the distribution of peak-to-valley height to length ratio K R consisting of the joint evaluation of 4 measurement section for each wall as well as a normalize standard gaussian distribution for each spectrum, keeping in mind that larger values of K R represent higher stress concentration at least for a first approach.

Fig. 7: Comparison of the K R ratio of three different WAAM walls

The K R spectrum of the optically roughest wall C shows highest K R values over the entire measured distance. The values are almost twice as high as for wall B. Furthermore, due to the spectrum shape, it can almost be assumed that the maximum K R value has been recorded. The spectrum shape of wall A seems to consist of two different distributions. The first one represents a smooth surface and contains most of the notches. The second is characterized by few notches with significantly higher deflections. This may indicate an abnormality such as a welding defect. Tracing back to the measuring point could provide further information here. In order to meet the basic idea of the Representative Structural Elements, i.e. an integral characteristic value, both the maximum value and the spectrum shape are needed to be able to define the range of validity.