PSI - Issue 57

Philipp Ladendorf et al. / Procedia Structural Integrity 57 (2024) 589–597 Ladendorf, Herion, Winkler, Dürr / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 7. Connection lengths l A of con entional K-joint and ariant 2

Fig. 8. F atigue strength minima and maxima and scaled relati e conneciton lengths Λ for load -case AX – brace H.S.

While the calculated fatigue strength of the con entional RHS is lowest for the load-case AX, ariant 1 is slightly higher, followed by ariants 2 and 3 with ariant 3 ranking highest. Although the Λ - alue for ariant 3 is nearly four times as high as the con entional RHS-K-joint, the fatigue strengths are nearly three times as high. Regarding the in estigated CHS-geometries, ariant 1 shows the lowest fatigue strength, which is lower than the con entional ge ometry. The highest fatigue strength can be achie ed using ariant 2, which has, besides the higher fatigue strength compared to ariant 3, also a smaller Λ - alue and is therefore more cost-effecti e. In practical applications, if the fatigue capacity of a con entional fatigue-loaded truss depends on the highest uti lized K-joint, the design could locally be altered using, for example, RHS-gusset-plate ariant 3 or CHS- ariant 2 to achie e a more economic o erall result. 4. Experimental investigations Throughout the term of the research project P1442, se eral fatigue tests ha e been performed at single joints (SJ) and truss specimens made of RHS-geometry no. 3, with con entional and gusset-plate K-joints and one test series made of the CHS-geometry no. 3 (cp. Table 3). Fig. 9 shows the test-setup for the single joints (loading with one hydraulic jack) and the truss specimens.