Piezoelectric Control of Edge Debonding in Beams Strengthened with Composite Materials: Part II - Failure Criteria and Optimization

Abstract

The prevention of the edge debonding failure in RC beams strengthened with externally bonded composite materials by means of optimized piezoelectric control is investigated. The study uses the mathematical model derived and verified in Part I of this paper to assess the structural response of the strengthened beam to the electrical and mechanical loads. The electrical actuation is optimized using two objective functions corresponding to two approaches for the prediction of the debonding failure. The first approach is based on evaluation of the stresses at the critical region near the edge of the bonded strip. The second approach adopts the fracture mechanics concept of the energy release rate, which is evaluated through the generalized J-integral. The formulation of the objective functions and the constraints associated with the restricted operational range of the piezoelectric actuators is presented. A procedure for the construction of the linear or quadratic response and objective functions through a relatively small number of evaluations of the structural model is presented and discussed. A numerical optimization study that focuses on the ability of different combinations of piezoelectric actuators to control, prevent, or delay the edge debonding failure is presented. The main contribution of this study is in providing a systematic approach to optimize the piezoelectric control under different debonding failure criteria and in demonstrating the feasibility of using the piezoelectric system in the full-scale civil engineering structure.

Piezoelectric Control of Edge Debonding in Beams Strengthened with Composite Materials: Part I – Analytical Modeling

“…Such approach would systematically provide guidelines for the design and optimal activation of the piezoelectric system. This issue is addressed in Part II of this paper [51].…”

“…The sensitivity of FE model also highlights the ambiguity associated with adopting the peak tensile stress as the quantitative criterion for the debonding initiation. This aspect is further studied in Part II of this paper [51]. Another aspect of the design of the active system is the location of the actuator (with respect to the edge of the bonded strip, see Figure 3(d)).…”

“…Hence, along with the enhanced electromechanical properties, the use of fibrous piezoelectric materials in the longitudinal direction can avoid the formation of stresses in the width direction. The use of the MFC actuators is examined in Part II of this paper [51].…”

Survey of Active Structural Control and Repair Using Piezoelectric Patches

“…The investigation was done on the bonded composite strip and based on the localized stresses near its edge. Later on, the same author extended his work in [65], and through composite patches he gave the piezoelectric design optimization for the control of the edge-debonding failure in the reinforced beam, as well as the criteria for failure. Included in his work was the presentation of an optimization study based on numerical methods that reflected upon various piezoelectric actuator combinations in controlling the failure of edge-debonding.…”

Applications of Piezoelectric Materials in Structural Health Monitoring and Repair: Selected Research Examples

“…Pioneering researches on repair of damaged steel structures by use of piezoelectric patches were conducted by Wang et al [ 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 ]. The concept was also extended to the repair of reinforced concrete beams [ 59 , 60 ], damaged structures with a moving mass [ 61 ], and analyzed by analytical fracture mechanics [ 62 ] and boundary element methods [ 63 ].…”