Buckling-driven debonding in stiff block: compliant joint structural assemblies patched with composite materials

Abstract

The initiation, growth, and stability of buckling driven debonding in structural assemblies of stiff blocks, compliant joints, and adhesively bonded composite layers are analytically investigated. The model is developed with focus on masonry walls externally strengthened with composite materials where static and, mainly, dynamic loads may induce compression in the strengthening layers triggering a buckling driven debonding near the joints. The model introduces the interfacial nonlinearity (debonding) through a cohesive interface approach. The geometrical nonlinearity is introduced through the kinematics of intermediate class of deformation (large deflections, moderate rotations, small strains), and the material nonlinearity of the masonry construction is introduced through the constitutive law for the mortar joints. A numerical study of the debonding process in strengthened masonry walls is presented. The study uses the periodicity of the wall for sub-structuring and examines configurations that include composite strips or sheets, strengthening on one face of the wall or on both faces, and compliant mortar materials.

Dynamics of FRP strengthened unidirectional masonry walls, I: A multilayered finite element

“…As such, it cannot be implemented in a classical, displacement based, finite element formulation. Alternatively, the functional form of the displacement field derived in the same references; i.e.,the parabolic and cubic out-of-plane and longitudinal displacements, respectively, is adopted here for a displacement based formulation (also see [Buller 2005;Elmalich and Rabinovitch 2009;2010]). This aims to take advantage of the close form solution of the 2D elasticity equations but yet to handle it through a displacement based form.…”

“…Wrinkling and local buckling when the thin FRP strips are subjected to compressive stresses (a scenario that may be inevitable under dynamic loads) and global instability or snap-through of the entire wall Hamed and Rabinovitch 2007a] stem from geometrical nonlinearity. The potential evolution of debonding and interlaminar cracking is involved with interfacial nonlinearities [Rabinovitch 2010]. …”

“…However, these models are limited to the linear elastic and static case [Buller 2005], the quasinonlinear, elastic, and static case [Elmalich and Rabinovitch 2009], or the physically nonlinear but static case [Elmalich and 4 ODED RABINOVITCH AND HAZEM MADAH Rabinovitch 2010]. As such, these models cannot address the unique features of the nonlinear, inelastic, and dynamic response of the strengthened masonry wall studied here.…”

High-order crack propagation in compressed sandwich panels

“…For the sake of convenience, a change of variables based on the boundary conditions terms (equations (10) and (11)…”

“…The buckling-driven debonding mechanism in structures comprised of masonry units sandwiched between adhesively bonded composite face sheets is investigated in Rabinovitch [11,12]. The investigation uses an analytical model that combines the classical HSAPT with cohesive interfaces located a few millimeters within the masonry substrate layer.…”