Fatigue of structures and secondary bending in structural elements

Observations and analyses of secondary bending for riveted lap joints

“…To this end the model will be applied to compute S b,max and S b,min in Eq. (12) employing Eq. (7) (x i = x 1 = L 1 ) and the scatter of the (S + S b ) a vs. N f data for various joint configurations will be compared to that exhibited in the case of the commonly used S a vs. N f presentation, where S a = (S max À S min )/2 is the applied stress amplitude.…”

“…The literature sources reviewed in a book by two of the present authors [1] (chapter 2, pp. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] indicate that fatigue tests under uniaxial loading provide conservative results on the fatigue performance of flat, biaxially loaded riveted specimens. Hence, uniaxial cyclic loading on the lap joints, which represents hoop stress variations in the skin, is considered in the present work, as in most other theoretical and experimental studies.…”

“…[1], this model predicts a very large effect of the amount of clamping on the SB magnitude, which is against the addressed above results for mechanically fastened joints. In contrast to the Barrois's model, the presence of fasteners is disregarded in approaches proposed by Schijve [11] (outlined in [12]) and Das et al [13] based on the elementary theory of elastic bending of beams or flat shells. The present authors proved the beam model to come in useful for studying the dependency of SB in lap joints on some geometric variables and the applied load level [1,14].…”

Influence of changes of the bending plane position on the fatigue life

“…In the literature there are many works devoted to the bending and its various aspects for example secondary bending in structural elements, or bending in high temperature . The problem of strength including a change of the bending plane position has not been presented in literature, except for the often occurring rotational bending typical for machine shafts.…”

Damage Monitoring in Composite Stiffened Skin Using Fiber Bragg Grating under Tensile and Three-Point Loading

“…Also, it is important to apply SHM technology in complex structures that have limited accessibility for inspections [1][2][3][4][5][6][7][8]. For example, a structure that has a stiffness mismatch has a high possibility to create a secondary bending moment on the edge of the stiffener, which has the potential to induce a delamination failure; this is highly dependent on the magnitude of the eccentricity and the flexural rigidity of the joint because the load transfer is not collinear through the mismatched-stiffness joint but is offset or eccentric [9][10].…”