Effect of Preformed Angle in Lap Zone on the Failure Procedure of Adhesively Bonded Aluminium Joint

The effect of the preformed deflection angle in the lap zone on the failure mode and the stresses distribution in the single-lap joint made of the epoxy adhesive and the aluminium adherend was investigated using elasto-plastic finite element method (FEM) and the experimental method of the shear strength testing. The failed surfaces were studied with the diagrams of scanning electron microscopy (SEM). The results from the numerical simulation showed that all the peak stresses in adhesively bonded single lap joint were decreased first and increased again as the preformed deflection angle was increased from 00 to 150. The lowest values occurred when the angle was taken as 100 and its strength is 22.1% higher than that of the standard one as the peak stresses were decreased and the stress distributed more evenly. The SEM images also show that the failure mode of the joint was transmitted from the adhesion to the mixed one as the deflection angle increased.

Download Full-text

Effect of Alkali on the Impact Toughness of Adhesively Bonded Joints

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.166-169.1904 ◽

2012 ◽

Vol 166-169 ◽

pp. 1904-1907

Author(s):

Min You ◽

Chun Zhi Mei ◽

Wen Jun Liu ◽

Jing Rong Hu ◽

Ling Wu

Keyword(s):

Impact Toughness ◽

Moisture Absorption ◽

Adhesive Layer ◽

Epoxy Adhesive ◽

Alkali Solution ◽

Lap Joint ◽

Adhesively Bonded ◽

Adhesively Bonded Joints ◽

Single Lap Joint ◽

The Impact

The effect of the temperature and immersed time of the alkali solution on the impact toughness of the adhesively bonded steel single lap joint under impact loading is studied using the experimental method. The results obtained show that the impact toughness of the specimen increased when the immersed time increased then it decreased as it beyond 3 days. When the immersed time is longer than 72 h, the higher the temperature is, the lower the impact toughness of the joint. The moisture absorption of the adhesive layer with the immersed time was also investigated and it was found that there is a relationship to the impact toughness of the adhesively bonded single lap joint. The epoxy adhesive layer was analyzed with FT-IR and it was found that the hydroxyl enhanced and bonding strength may increase after 72 h immersed in alkali solution.

Download Full-text

JOINT STRENGTH OF MIXED SILYL MODIFIED POLYMER-EPOXY ADHESIVE ON SINGLE LAP JOINT ETCHED ALUMINUM

Jurnal Teknologi ◽

10.11113/jt.v79.11873 ◽

2017 ◽

Vol 79 (7-2) ◽

Cited By ~ 1

Author(s):

Sri Hastuti ◽

Neng Sri Suharty ◽

Triyono Triyono

Keyword(s):

Failure Mode ◽

Adhesive Joint ◽

Joint Strength ◽

Epoxy Adhesive ◽

Experimental Result ◽

Aluminum Surface ◽

Lap Joint ◽

Single Lap Joint ◽

Modified Polymer ◽

Bus Body

Currently, aluminum alloy is widely used in an automotive structure such as bus body materials due to decreasing the structure weight and fuel consumption. In this structure, there are tens or even hundreds of joints to meet the engineering design. Because of its advantages, the adhesive joint is usually chosen. Aluminum is stiff enough, but it can deform easily. Due to its deformability, cracks will occur easily on the aluminum adhesive joint if it is joined using strong and stiff adhesive. Otherwise, it will be very weak if it is joined using flexible adhesive. The mixture of the strong adhesive, epoxy (EP) and the ductile adhesive, silyl modified polymer (SMP) was proposed for joining aluminum. This study aims to evaluate the effect of the composition of mixed adhesive and its thickness on the strength of single lap joint (SLJ) etched aluminum. Before joining process, the aluminum surface was treated by sandpapering (SDP), and then chromic-sulphuric acid (CSA) etch. The composition variations of mixed adhesive were 100%EP, 75%SMP:25%EP, 50%SMP:50%EP, 25%SMP:75%EP, and 100%SMP. Mixed adhesives were prepared by using a stirrer with a spatula for 4-6 minutes at 60 rpm. SLJ specimens were manufactured through bonding of two aluminum sheets surface with an adhesive and giving 0.1 MPa pressure. The thickness adhesive was varied of 0.2 mm, 0.4 mm, and 0.6 mm. Specimens got a post-curing process at 100oC for 100 minutes. The shear tests were performed to evaluate the strength of SLJ. The experimental result showed that the surface treatments of SDP and CSA give higher porosity on the adherend surface. The highest strength and elasticity modulus were achieved by joint of 25%SMP:75%EP mixed adhesive joints. The addition a few of SMP adhesive in EP adhesive and adherend surface treatment increases the joint strength. All of the joints have mixed failure mode except the 100%EP adhesive joint has an adhesive failure mode.

Download Full-text