Effects Of Adhesive Properties Research Articles

Numerical Investigation of Interfacial Stress Distribution in Adhesive-Bonded Joints for Different Adhesive Materials

The widespread use of adhesive bonded connections has been used in a range of technical fields. In this paper, the interfacial stress distribution of adhesive bonded joint is presented. When determining whether or not a structure is dependable for use in operation, the stresses that act along the bond line of an adhesively bonded lap joint are of the utmost importance. The purpose of this study is to develop finite element solutions that are able to anticipate shear and peel stresses using the theory of elasticity as their foundation. The effect of adhesive properties on stress distribution is investigated by using different adhesive materials. By analysing five different adhesive materials it is concluded that ‘adhesive I’ is more reliable for operation.

Effect of adhesive properties on the bond behaviour of externally bonded FRP-to-concrete joints

The influence of adhesive properties on the bond behaviour of externally bonded fibre-reinforced polymer (FRP)-to-concrete joints is the focus of this paper. First, FRP-to-concrete double-lap shear specimens were tested with different types of bonding adhesives. The test results indicate that when softer adhesives are adopted, the peak load, interfacial fracture energy and FRP effective bond length increase while the peak shear stress decreases. Then, a finite element (FE) model including the adhesive layer was proposed to further investigate the influence mechanism of the adhesive properties. A numerical parametric study indicates that the adhesive tensile strength, ultimate strain, elastic modulus and thickness all have varying degrees of impact on the bond behaviour of FRP-to-concrete joints. Finally, a bond-slip model that considers the adhesive elastic modulus is proposed based on experimental and numerical results. To validate this model, a comprehensive test database that includes 128 FRP-to-concrete joints with different adhesives was collected. The proposed model has been shown to have a higher accuracy and lower dispersion than the existing models for the prediction of the peak loads of FRP-to-concrete joints with different adhesives.

各種配向性ファイバーボードをコアにしたサンドイッチパネルの寸法安定性能の解析的研究

The observed values of dimensional stabilities(thickness swelling (TS) or linear expansion (LE)) for sandwich panels with veneer or paper as the faces and various oriented fiberboards as the core were compared with the values calculated by the properties of veneer, paper or various oriented fiberboards. As a result, observed TS or LE values agreed basically well with calculated ones , however, it was important for calculated value of higher precision to consider the effect of adhesive properties between face and core. Dimensional stabilities of sandwich panel could be estimated by the properties of face and core materials of composites. If face material had high Young's modulus and great dimensional stabilities like the veneer in fiber direction with the poor dimensional stabilities of core material, sandwich panel would have great dimensional stabilities.

An experimental study of different factors affecting the bond of NSM FRP bars in concrete

Near-surface mounted (NSM) fiber reinforced polymer (FRP) reinforcement has proven to be an efficient technique for strengthening concrete members. The bond behavior of the NSM system depends on the bond in the two existing interfaces, while the response in terms of load–slip curves and load capacity may be strongly affected by many other parameters. As a consequence of the variety of factors affecting the bond, different studies into the behavior of NSM FRP reinforcement have been carried out in recent years. In this paper, an experimental study is performed in which the effect of adhesive properties, bar type, bar size, FRP properties, groove geometry and the use of mechanical interlocking on the capacity and bond behavior of a NSM joint is investigated. The failure load, average bond stress, loaded end slip, free end slip, transverse strains (on adhesive and concrete), and the mode of failure for the tested joints are reported and discussed. The results show that the adhesive properties, FRP bar size and bar surface treatment were critical factors in the capacity and mode of failure of the specimens tested.

Mechanical damping using adhesive micro or nano powders

A particle dynamics simulation model is developed and used to design a mechanical damping device that uses micro or nano powders as the damping medium. A damping device based on a powder has the advantage over the traditional use of a viscous fluid of temperature insensitive operation. Adhesion forces significantly affect the behavior of small particles. The damping mechanism targeted stems from energy dissipated due to the breaking of many adhesive particle contacts. Adhesive contacts can dissipate energy due to hysteresis in the force between particle loading and unloading. In this work adhesion hysteresis is added to the JKR model of adhesive contact and then used in particle dynamics simulations. The effects of adhesive properties and packing densities are studied in two device geometries (shear and piston) using simulation.

The effect of adhesive properties on the low temperature strength of joints between metals and carbon fibre- reinforced plastics

The adhesive in joints between metals and carbon fibre-reinforced composites is usually under stress due to differential adherend contraction on cooling from the cure temperature. This stress can greatly reduce joint strengths at —55°C, as was confirmed for three adhesives. In contrast, a fourth adhesive gave relatively high strength at —55°C, probably because of its higher strain-to-failure. Strengths were much higher when titanium was substituted for aluminium, the former having a much lower expansion coefficient. However, lower cure temperatures did not increase strengths, possibly because the adhesives did not develop their full toughness.