PSI - Issue 76

Filip Likavčan et al. / Procedia Structural Integrity 76 (2026) 145– 150

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Fig. 3. Comparison of fatigue S-N curves of aluminum alloy Al6061 in T6 condition and after welding.

Another consequence of bicycle frame manufacturing technology is the resulting geometric deviations from the ideal shape. The non-parallelism of the head tubes, seat tubes, and possibly parts of the motor housing with the overall longitudinal axis of the bicycle generates additional torsional stress when the frame is loaded during riding and when overcoming obstacles (see Figs. 4 and 5).

Fig. 4. Deviations in the geometry of the bicycle frame.

Fig. 5. Additional shear stresses from torsion on the seat tube and steering tube measured while riding on the bicycle frame..