TABLE OF CONTENTS At the macroscopic level, bolted plates deform elastically, as in Fig. 8.12. Separation of plates, though exaggerated in the figure, does occur, and at relatively small distances from the bolt. In its most basic statement, the bolted-joint problem can be considered the contact-conductance problem for a nonuniform interface pressure. Figure 8.13(a) shows schematics of an interfacial pressure profile with ( ? > 0) and without ( ? = 0) roughness.
An excellent theoretical treatment of this subject has been provided by Roca and Mikic [8.28] , [8.29] for plates that are nominally flat when unstressed. Roca and Mikic extended the theory beyond the single-plate midplane work of Fernlund [8.30] and others to two plates with surface roughness. The biharmonic equation was used to characterize the elastic deformation of the plates. Their method assumed that deformation of the plates is elastic, asperity height above a mean plane is Gaussian, and asperity contact is normal with no tangential component. Both plastic and elastic asperity deformation were treated. The structural model used is shown in Fig. 8.13(b), and typical calculated results obtained using an iterative method are shown in Fig. 8.13(c).
The thermal model used by...
