PSI - Issue 68

Pascal Franck et al. / Procedia Structural Integrity 68 (2025) 119–125 P. Franck et al./ Structural Integrity Procedia 00 (2025) 000–000

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a little wider and it seems, that the loop is tilting a little bit towards the end of the test. This indicates ongoing plastic damage to the specimen.

(a)

(b)

Fig. 5. Constant amplitude test with a maximum stress of 55 MPa: (a) localization of high-loaded areas and (b) hysteresis loops of the beginning and end of the test using digital image correlation.

Together with further CAT on different load levels, the desired Woehler curve for the laminated bamboo lumber was estimated. Fig. 6 shows the Woehler curve determined following the Basquin equation. All specimens that failed due to the applied load were included in the calculation. The Basquin fit, with the equation shown in the diagram, was suitable for estimating the test results obtained. The coefficient of determination for the fit was R 2 = 0.96. Additionally, the load levels and the average number of cycles to failure are once more shown in Table 1.

Fig. 6. First assessment of a Woehler curve for the laminated bamboo lumber material.