Tubular bonded joint under torsion: Theoretical analysis and optimization for uniform torsional strength

Abstract

The paper analyses the problem of torsion in an adhesive bonded tubular joint. The constitutive, equilibrium and compatibility equations were used to obtain the stress field in the adhesive. The analysis confirms that the maximum stresses are attained at the ends of the adhesive and that the peak of maximum stress is reached at the end of the stiffer tube and does not tend to zero as the adhesive length approaches infinity.A special type of tubular joint can be produced by modifying the joint profile, thus ensuring that the stress field in the adhesive is constant and thereby optimizing the tubular joint for uniform torsional strength. This result is of considerable practical utility and makes it possible to produce adhesive bonded joints which are both lighter and stronger under torsion. Finally, some suggestions for the joint design are presented.

A generalization of the Coulomb’s friction law: from graphene to macroscale

“…Following [18][19][20][21][22], we find the identical result reported in Eq. (4b), if we assume an equivalent dissipated energy per unit surface 2γ given by:…”

“…We treat the scheme reported in Fig. 1(a) according to elasticity and energy balance, following previous approaches [18][19][20][21][22][23]; in this paper we introduce friction (i) and we demonstrate that the sliding can be treated as a "delamination" but taking place at a reduced "equivalent surface energy" that is correlated to friction and adhesion (ii). Accordingly, following [18][19][20][21][22][23], the solution posed by elasticity for the maximum shear stress arising at the interface of the two layers (the stress peak will take place at the end of the element with the higher rigidity, thus is symmetric for our considered identical layers), having Young's modulus E 1,2 (E 1,2 = E for identical layers), crosssectional areas A 1,2 (A 1,2 = A = bh for identical layers) and contact length l = 2c, in the presence of friction becomes: …”

“…Is friction dominated by the friction shear strength, by the friction force or by the dissipated energy? Coupling elasticity and energy balance [18][19][20][21][22][23][24][25][26][27] with molecular dynamics (MD) [27][28][29][30] and statistical simulations [31][32][33][34] we solve in this paper such controversy.…”

Strength, stability and size effects in the brittle behaviour of bonded joints under torsion: theory and experimental assessment

“…An extension considering tapered adherends has been also presented 5 . Pugno 6 and Pugno and Surace 7 have considered the non‐tubular and tubular joint as streamlined for uniform torsional strength ( uts ): starting from a non‐tapered joint, the optimization was achieved by chamfering the edges, which are in any case not involved in the stress flow induced by the load for which the joint should be designed. The resulting optimized joint shape is thus both lighter and stronger.…”

Thermal loading in multi-layered and/or functionally graded materials: Residual stress field, delamination, fatigue and related size effects

“…The axial equilibrium along the longitudinal axis (x) provides the tangential stresses at the interface of the two layers ( Fig. 1) (Pugno and Surace, 2001):…”