| Most of the ancient buildings left over from history are brick and wood structures,of which the wood is prone to cracking and deformation,unstable strength and other shortcomings.With the passage of years,environmental erosion and the impact of natural disasters such as earthquake and lightning strike,the mechanical properties of wood structures gradually decline,which can not meet the requirements of continuing to bear external loads.It is very urgent to put forward appropriate methods to enhance the mechanical properties of wood structural members and to study the technologies and ways to improve the properties of reinforcement materials.Fiber reinforced polymer/plastic(FRP for short,the same below)is composed of continuous fiber and resin matrix.It has the advantages of high strength to weight ratio and convenient processing,and is widely used in strengthening concrete structures.In recent years,this technology has also been applied to the field of wood structure.The bond performance of FRP wood interface plays a very important role in the effect of strengthening wood structures.In this paper,the effects of adhesive types and bonding thickness on the bonding properties of FRP wood interface were studied.The specific contents and conclusions are as follows:(1)Through the single-sided shear test of FRP wood structure,the effects of adhesive type and adhesive layer thickness on the ultimate bearing capacity and failure mode,load displacement relationship,FRP strain distribution,bond slip relationship,shear stress distribution and interface fracture energy of FRP wood interface were studied.The results show that the ultimate bearing capacity of the interface between epoxy T1 adhesive and dp420 adhesive is greater than that of polyurethane adhesive dp620ns;The interface ultimate bearing capacity with adhesive layer thickness of 0.5mm is greater than 3mm.(2)Based on the results of single-sided shear test and related literature,a constitutive model of flax fiber wood interface with different adhesive layer thickness was proposed.The trilinear model is used to fit the bond slip test curve of carbon fiber wood interface,which is in good agreement.(3)In the analysis of the two test variables of adhesive layer thickness and adhesive type,the cohesive element and spring2 spring element are proposed to simulate the adhesive part of FRP wood structure single-sided shear specimens respectively,and the finite element analysis of the interface is carried out by ABAQUS.The simulated value of the ultimate bearing capacity of FRP wood interface is compared with the experimental value,and the difference between the two results is small,which proves that the selected element is feasible to simulate the FRP wood interface adhesive layer.It has reference value for the analysis of similar problems. |
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