Influence of Rivet Tip Geometry on the Joint Quality and Mechanical Strengths of Self-Piercing Riveted Aluminium Joints

2013 ◽  
Vol 765 ◽  
pp. 746-750 ◽  
Author(s):  
De Zhi Li ◽  
Li Han ◽  
Mike Shergold ◽  
Martin Thornton ◽  
Geraint Williams
Keyword(s):  
Automotive Industry ◽  
Fuel Efficiency ◽  
Peel Strength ◽  
Strength Reduction ◽  
Lap Shear Strength ◽  
Lightweight Structures ◽  
Lap Shear ◽  
Riveting Process ◽  
Joint Quality ◽  
Mechanical Strengths

Due to the drive from legislations, fuel efficiency, and CO2 emission, the application of aluminium lightweight structures in automotive industry have been increased significantly. Self piercing riveting (SPR) has been one of the major joining technologies for aluminium structures due to its advantages to some traditional joining technologies. There are some standard parameters that will influence the joint quality and mechanical strengths of an SPR joint. However, even for the same parameters used, sometimes the joint quality and mechanical strengths of SPR joints could still be significantly different, which may cause joint failure or strength reduction. One reason found is the variation of rivet specifications between different batches. In this paper, the influence of rivet tip geometry on the joint quality and mechanical strengths was studied. The results showed that rivets with sharper tips flared more during riveting process, and joints with sharper rivets had higher lap shear strength; however, the influence of rivet geometry on T peel strength could be different for different rivets, and rivet tip geometry did not have an obvious influence on joint fatigue strengths.

Influence of Die Profiles and Cracks on Joint Buttons on the Joint Quality and Mechanical Strengths of High Strength Aluminium Alloy Joint

2012 ◽  
Vol 548 ◽  
pp. 398-405 ◽  
Author(s):  
De Zhi Li ◽  
Li Han ◽  
Zong Jin Lu ◽  
Martin Thornton ◽  
Mike Shergold
Keyword(s):  
Aluminium Alloy ◽  
High Strength ◽  
Bottom Layer ◽  
Peel Strength ◽  
Lap Shear Strength ◽  
Lap Shear ◽  
Increase Productivity ◽  
Small Cracks ◽  
Joint Quality ◽  
Mechanical Strengths

Currently, self-piercing riveting (SPR) is a major technology used by manufacturers to join aluminium body structures to reduce vehicle weight. Normally, for SPR of one specific stack more than one die, rivet, and velocity combination can be applied. Which parameter combination is chosen is depending on the surrounding joints. In order to increase productivity and reduce the number of robots used, it is preferred to use the same rivet/die combination for as many joints as possible. This means for the same stack, different die may be used. To see the influence of die profiles on joint quality, a DF die, which would generate severe cracks and a DC die, which would generate no cracks or only small cracks, were used to join two stacks with a high strength aluminium alloy, AA6008T61, as the bottom layer. The joint quality was analyzed, and the static and fatigue strengths of these stacks were studied. Results showed that cracks on joint buttons might reduce static and fatigue lap shear strength but had no obvious influence on static and fatigue T peel strength for the joints studied.

scholarly journals Prediction of Lap Shear Strength and Impact Peel Strength of Epoxy Adhesive by Machine Learning Approach

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 872
Author(s):  
Haisu Kang ◽  
Ji Hee Lee ◽  
Youngson Choe ◽  
Seung Geol Lee
Keyword(s):  
Machine Learning ◽  
Shear Strength ◽  
Linear Correlation ◽  
Peel Strength ◽  
Epoxy Adhesive ◽  
Data Sets ◽  
Ann Model ◽  
Lap Shear Strength ◽  
Lap Shear ◽  
The Impact

In this study, an artificial neural network (ANN), which is a machine learning (ML) method, is used to predict the adhesion strength of structural epoxy adhesives. The data sets were obtained by testing the lap shear strength at room temperature and the impact peel strength at −40 °C for specimens of various epoxy adhesive formulations. The linear correlation analysis showed that the content of the catalyst, flexibilizer, and the curing agent in the epoxy formulation exhibited the highest correlation with the lap shear strength. Using the analyzed data sets, we constructed an ANN model and optimized it with the selection set and training set divided from the data sets. The obtained root mean square error (RMSE) and R2 values confirmed that each model was a suitable predictive model. The change of the lap shear strength and impact peel strength was predicted according to the change in the content of components shown to have a high linear correlation with the lap shear strength and the impact peel strength. Consequently, the contents of the formulation components that resulted in the optimum adhesive strength of epoxy were obtained by our prediction model.

Heat-Sealing Properties of Compression-Molded Wheat Gluten Films

2007 ◽  
Vol 1 (1) ◽  
pp. 56-63 ◽  
Author(s):  
Sung-Woo Cho ◽  
Henrik Ullsten ◽  
Mikael Gällstedt ◽  
Mikael S. Hedenqvist
Keyword(s):  
Shear Strength ◽  
Wheat Gluten ◽  
Peel Test ◽  
Mold Temperature ◽  
Peel Strength ◽  
Minor Effect ◽  
Lap Shear Strength ◽  
Lap Shear ◽  
Heat Sealing ◽  
A Minor

The impulse heat-sealing properties of wheat gluten films were investigated. Films containing 30 wt% glycerol were compression molded at 100–130 °C and then sealed in a lap-shear or peel-test geometry at 120–175 °C. The tensile properties of the pristine films and the lap-shear and peel strength of the sealed films were evaluated and the seals were examined by scanning electron microscopy. Glycerol was added to the film surfaces prior to sealing in an attempt to enhance the seal strength. It was observed that the wheat gluten films were readily sealable. At a 120 °C sealing temperature and without glycerol as adhesive, the lap-shear strength was greater than or similar to that of polyethylene film, although the peel strength was poorer. The sealing temperature had a negligible effect on the lap-shear strength, but the peel strength increased with sealing temperature. The lap-shear strength increased with increasing mold temperature and the failure mode changed, especially in the absence of glycerol adhesive, from a cohesive (material failure) to an adhesive type. From previous results, it is known that the high-temperature (130 °C) compression-molded film was highly cross-linked and aggregated, and this prevents molecular interdiffusion and entanglement and thus leads to incomplete seal fusion and, in general, adhesive failure. The presence of glycerol adhesive had a beneficial affect on the peel strength but no, or only a minor, effect on the lap-shear strength.

scholarly journals Effect of Nylon-6 Concentration on the Properties of Hot Melt Adhesive Synthesized using Dimer Acid and Ethylenediamine

2012 ◽  
Vol 9 (2) ◽  
pp. 215-215
Author(s):  
PRAVIN G. KADAM ◽  
SHASHANK T. MHASKE
Keyword(s):  
Tensile Strength ◽  
Tensile Modulus ◽  
Nylon 6 ◽  
Peel Strength ◽  
Percentage Elongation ◽  
Elongation At Break ◽  
Lap Shear Strength ◽  
Lap Shear ◽  
Enthalpy Of Melting ◽  
Hot Melt

Hot melt adhesive synthesized using polymerized fatty acid (PFA) (composition: ~1% trilinoleic acid, ~97% dilinoleic acid and ~2% linoleic acid) and ethylenediamine was blended with nylon-6, in-situ during the synthesis process to improve its performance properties. Nylon-6 was added in concentrations as 5, 10, 15 and 20 phr in the hot melt adhesive. The prepared blends were characterized for thermal (melting temperature, crystallization temperature, enthalpy of melting and enthalpy of crystallization), mechanical (tensile strength, tensile modulus, stiffness, percentage elongation at break and hardness), adhesion (lap shear strength and T-peel strength) and rheological properties. It was found that the viscosity, tensile strength, tensile modulus, stiffness, hardness, melting temperature, enthalpy of melting, crystallization temperature and enthalpy of crystallization increased with increase in concentration of nylon-6 in the hot melt adhesive. But lap shear strength and T-peel strength increased up to 10 phr concentration of nylon-6 above which both started decreasing. Percentage elongation at break decreased with increase in concentration of nylon-6 in the hot melt adhesive. Hot melt adhesive molecules must have oriented themselves about nylon-6, increasing its crystallinity, and thus the strength of the adhesive.

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