دانلود رایگان مقاله انگلیسی برش سوراخ دار + رابط های نواری تقویتی در محلول کامپوزیت بتن الواری - الزویر 2019

ABSTRACT

This paper presents a study of a novel shear connector in a timber-concrete composite solution, focussing on the determination of an analytical expression that makes it possible to predict its behaviour and a numerical analysis that describes it accurately. The shear connector is composed of a perforated steel plate inserted into a slot within the timber rib and glued, in combination with reinforcing corrugated steel bars affixed to the top of the plate. Previous tests made it possible to establish failure mode in different T composite section plate-rebar configurations. These results determine the effectiveness of the system in terms of force-slip behaviour, with systematic failure in the timber section. A simple predictive model is proposed to determine the ultimate capacity of the joint, taking into account the mechanical properties of timber in relation with the fracture plane and the timber-adhesive interface. This model makes it possible to apply a design process that is able to predict the stiffness of the connection. FEM models were analysed for each configuration in a variable load process equal to that used in the test, according to the standard procedure. A variable friction coefficient in contact definition made it possible to achieve an accurate descriptive model in association with the test procedure.

 Conclusion

There are previous analytical expressions to describe the slip-load behaviour of a composite system, not being able to establish any relationship between the material and geometric configuration of the joint and the result obtained. Furthermore, in order to adequately describe the behaviour in the linear phase and in the plastic phase, they require the inclusion of correction factors, resulting in extremely complex expressions. The new proposal presents a simple expression that allows defining the behaviour in both phases, without needing to establish more correction factors and does so taking into account only two factors. On the one hand the geometry of the plate-timber contact zone (α) and on the other an ultimate load value (Fmax) supported by the joint. The determination of the failure mode has allowed to relate the ultimate load with the shear stress (τs) in the contact zone and with the timber shear strength (fv). It is therefore possible to establish a predictive load equivalent (Fpredict) for each geometric configuration from a given value of shear strength. Using this value in the proposed expression it is possible to predict the behaviour of the joint in load-slip terms. Therefore, this expression allows to establish a simple design rule for the determination of the slip module Ks. The proposed analytical model is therefore a design tool. The complexity of the FEM numerical model is directly related to the accuracy of its results. For stress-strain behaviour analyses it is extremely important to have a model that accurately reflects the influence of each geometric factor and each mechanical property of the constituent materials.