Investigation on the influence of adhesive properties on the formability of adhesive-bonded steel sheets

The Journal of Strain Analysis for Engineering Design

2014

Self Cite

In this investigation, the influence of artificial finite adhesive defects with different shapes and sizes, characterized by (1) aspect ratios, a/b = 0.5, 1 and 1.5 (where a is transverse axis length of defect; b is longitudinal axis length of defect), (2) number of defects and (3) different locations, in the epoxy adhesive layer on the formability of adhesive-bonded blanks, is analysed. The deep drawing quality cold-rolled steel and stainless steel (SS 316L) sheets were used as base materials. The increase in aspect ratio of adhesive defect reduces the ductility of adhesive layer and thereby decreases the formability of adhesive-bonded blanks. This is due to the early failure of adhesive layer at the location of defect where strain is locally concentrated. The strain hardening exponent (n) of adhesive-bonded blanks has decreased with increase in aspect ratio of adhesive defect in all the regions of deformation. The limit strain of deep drawing quality and SS 316L sheets constituting adhesive-bonded blanks shows decrement with increase in aspect ratio of adhesive defect. It is postulated that the aspect ratio of the finite adhesive defect influences significantly the formability of adhesive-bonded blanks, but not shape of the finite adhesive defects. There is no considerable effect of number of adhesive defects and different locations of adhesive defects on the formability of adhesive-bonded blanks.

Section: Resultsmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 94%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Formability of adhesive-bonded steel sheets with artificial finite adhesive defects

The Journal of Strain Analysis for Engineering Design

2014

Self Cite

“…The adhesive bonded tensile specimens were prepared according to ASTM E646-07 standard by using epoxy adhesive with hardener/resin ratio of 1:1 (by weight) for which the total elongation is higher as given in Table 3 and also larger formability was observed for the adhesive bonded blank with hardener/resin ratio of 1:1 in our previous investigations [9,10]. Fig.…”

Section: Methods Of Analysismentioning

confidence: 99%

Influence of Pre-Generated Infinite Adhesive Defects on the Forming Behaviour of Adhesive Bonded Steel Sheets

2014

AMR

In the present investigation, the forming behaviour of adhesive bonded sheets with the pre-generated infinite defects in the adhesive layer is studied. The infinite defects are generated with different orientations like longitudinal, transverse and at an angle of 45°. The base sheet materials used are deep drawing quality steel and SS 316L sheets, and two part epoxy adhesive is used for bonding the base sheet materials. The formability is quantified by monitoring the load-extension behaviour, and limit strain, evaluated through tensile tests and in-plane plane strain (IPPS) formability tests. It is observed that there is a significant decrease in formability because of the presence of infinite defects in the adhesive layer. While comparing the formability of adhesive bonded blanks with respect to different orientations, transversely oriented defect shows more reduction than 45° and longitudinal cases. There is not much difference between the transversely oriented and 45° oriented infinite defects in tensile tests, whereas in the IPPS formability test results, there is no considerable difference between 45° and longitudinally oriented defect.

Experimental evaluation and prediction of deep drawability of adhesive bonded steel sheets

Materialwissenschaft Werkst

2015

The main aim of the present work is to experimentally evaluate the deep drawing behaviour of adhesive bonded sheets at different adhesive properties and predict the same using finite element simulations. The deep drawing quality steel and SS316L stainless steel are used as base materials for experiments and simulations. The deep drawing behaviour is also predicted using available analytical equations and proposed semi‐empirical equations. Such predictions are validated with experimental results. It is observed that due to increased plasticity of adhesive layer, the hardener rich formulation of adhesive improves the deep drawability of adhesive bonded blanks. The presence of carbon black in the adhesive has improved the drawability of bonded sheets up to a certain limit, say 2% by weight in the present work. The deep drawing behaviour predicted either by approach 1 (by giving experimentally evaluated adhesive properties as input) and by approach 2 (adhesive properties evaluated from rule of mixtures) are almost same, which indicates that both the methods can be used for forming behaviour prediction. The deep drawability predictions are moderately accurate with respect to experimental observation. The accuracy of analytical models for maximum load predictions is encouraging while comparing it with experimental results and numerical predictions. The proposed semi‐empirical equations show promising results to obtain initial estimate about the load‐progression behaviour of bonded sheets.