Fully bonded bolts are divided into “bolt elements” according to where the bolts cross the finite element mesh. It is assumed a “perfect bond” between the truss element (bolt) and crossed plane elements. These bolt elements act independently of each other. Neighbouring fully bonded bolt elements do not influence each other directly, but only indirectly through their effect on the plane elements (Fig. 35).
|
Figure 35. Fully bonded bolts. |
The bolt stiffness matrix and nodal force vector are determined as in section 4.3.2, in function of the transformation matrix that depends of the shape functions of the crossed plane element.
The axial force along the bolt is determined from the relative axial displacements of the bolt element.
|
(136) |
where uj and ui represents the axial local displacements at ended nodes determined as in section 4.3.2.
When a plastic behaviour is selected for the fully bonded bolts, the failure of the bolt is assumed to occur if the axial force 
exceeds the yield strength of the bolt material. No residual force is allowed in this case (Fig. 34).
© 2020 GeoStru Software