Papers by Keyword: Adhesive Bonding

Abstract: We analyzed effects of interface/adhesive defects during fracture mechanical Mode I Double Cantilever Beam (DCB) tests of an adhesive joint. Two aluminium slabs were bonded using structural epoxy adhesive. A DCB experiment under static loading was conducted to estimate the critical fracture energy. During the ‘steady-state’ fracture we noted oscillating, random fluctuation in the force vs. displacement curve, and thus in the fracture energy. This is associated to the local variation of properties within the bondline and the interfaces. A simple model is derived to quantify the probable density of flaws observed experimentally.

Abstract: This paper demonstrates a unique application of DIC wherein the structural performance and structural integrity have been evaluated together almost in real-time. The results obtained from the ground level tests, simulating the bonding between the TPS to the base structure of a space crew module, are reported to find the adequacy of two different adhesives prior to actual bonding. The test objective was to characterize the adhesives based on the structural performance (deflection and strain behavior) of the TPS and conduct health monitoring in real-time (i.e. abort the test whenever the TPS fails). The dual objective could be met using DIC in a full-field and non-contact manner, which was essential due to the limitations of the contacting type measurements.

Abstract: This paper presents the results of an experimental investigation on mechanical characterization of adhesive T-joint in granulator fluidization bed at elevated temperature. This research aims to explore the suitability of adhesive bonding between stainless steel plate and perforated plate to replace plug weld in granulator fluidization bed. For this purpose, T-joint and bulk specimens were prepared for tensile loading tests, at different temperature. Measurement of the temperature-dependent of the tensile strength was conducted using thermostatic chamber attached to a universal testing machine for a range from room temperature to 100°C. The strength of adhesive T-joint decreases for temperatures over than 35°C. This is because at high temperature, the failure is determined by the changes of mechanical properties of adhesive. The results have shown that the strength of adhesive T-joint was affected by both temperature and bondline thickness. The objective of the present study was to examine a series of adhesively-bonded T-joints in tension at elevated temperatures between room temperature and 100°C having various bond thicknesses.

Abstract: In this investigation surface treatment of titanium alloy VT20 is carried out by phosphating and anodization in order to increase the adhesive bond strength. The surfaces were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), profilometry, contact angle measurements. The joined titanium specimens were shear tested before and after exposure to high humidity to a period of three months.

Abstract: In practice, adhesive bonded joints are loaded by different intensity and rate. In the case where bond bearing capacity is exceeded, failure occurs. One of the affecting factors is strain rate. In the laboratory tests, ČSN EN 1465 is used as a basic standard, specifying the rate of deformation in the interval of 65±20 seconds. The goal of this research is to describe the behaviour of two-part epoxy adhesives at different strain rate of bonded joints. Experiments evaluated the changes of bond strength, deformation and time to failure. Time to failure is particularly significant because of the potential consequences of fast structural joint violation.

Abstract: Weldability of magnesium alloy to aluminum alloy in laser weld bonded (LWB) joints are investigated. Results showed that magnesium/aluminum could be easily joined by LWB under proper technological parameters. The weld is characterized by complex vortex flow at the bottom and there existed intermetallic compound layer between weld pool and lower sheet metal which was composed of the brittle phases of Al₃Mg₂. The aim of this research is to evaluate the weldability using LWD process to join Mg/Al alloys using HLD 3504 – Laser Type Trumpf, to explain the experimental conditions and interpretation of results.

Abstract: This paper focus on the Oxygen plasma surface treatment affect on the bonding strength. In shearing force tests , total 10 samples were tested. Through the shear force tests, it indicates that moderate exposure to O₂ plasma could increase the bonding strength to some extent. Then the AFM tests results shows that the MR-I 9100M coating topography is about 14 nm, while after Oxygen plasma treatment the topograhy decrease to 7.9 nm. And the MR-I 9150M coating topography is about 5.5 nm, while after Oxygen plasma treatment the topograhy decrease to 4.6 nm. By AFM tests, it can be found that the Oxygen plasma surface treatment cause the decrease of the surface roughness. And it puts forward another possible explanation for the Oxygen plasma treatment can improve the bonding strength.

Abstract: In this paper, structural adhesive SikaPower-498 is associated with spot welds to produce weld bonded joint with KS2 specimens. The specimens are tested under tension, shear and peeling loading. Weld bonded joint ultimate strength and energy absorption are compared with single spot welded joints and adhesively bonded joints tests. In order to investigate the facture mechanism of weld bonded joint, optical microscopy and scanning electronic microscopy are used to check the material structure and the facture surfaces respectively. Weld bonded joints show the highest ultimate strength and energy absorption under tension and peeling test among the three tests while it has intermediate ultimate strength and the lowest energy absorption under shear. Fracture analysis shows that spot welds fail in ductile fracture. The results can be used to design weld bonded joint in car body-in-white and to calibrate modeling parameters for weld bonded joint modeling in finite element calculations.

Abstract: Stress analysis of adhesive bonding of urea granulator fluidization bed was performed by using finite element method. The main objective of this project is to develop an alternative joining technique for urea granulator fluidizationbed by using adhesive bonding. The problem can solve by using commercial finite element package ANSYS version 13.0. T-joint and double T-joint are the main adhesive joints which will be focused in this project. The stresses on stainless steel plate can reduce by increasing the thickness of adhesive as demonstrated in numerical analysis results. Different thickness of adhesive will give different value of maximum von Mises stress. It shows that greater thickness resulted in higher maximum. This analysis proves that increasing the adhesive thickness will reduces the joint strength because stress was concentrated more on the adhesive interfaces. The adhesive bonding on T-joint is stronger than other design of joint because it need lower stress. It followed by first design of double T-joint and second design of double T-joint.

Abstract: In this work, piezoresistive stress sensors test circuit fabricated into the sensitive structure as part of the normal processing procedure is used to measure the stresses difference distribution before and after the assembly. Sensor resistances were recorded before and after the adhesive bonding. Using the theoretical equations, the stresses on the die surface have been calculated from the data of sensor resistances. This technology not only provides a performance diagnostic tool for the sensitive structures and the miniature components, but also presents a design tool for low-stress micro-assemblies of miniature components.