Load transfer in hybrid (bonded/bolted) composite single-lap joints

2005 ◽  
Vol 69 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Gordon Kelly
Author(s):  
Sayed A. Nassar ◽  
Kassem Moustafa ◽  
Zhijun Wu ◽  
Demetrios Tzelepis

An experimental procedure and test setup is used for investigating effect of using nanoparticle additives to the adhesive on the load transfer capacity (LTC) of bonded magnesium (Mg)-steel (St) single lap joints (SLJ). Investigated variables include the nano-powder material (Alumina vs. Silica), particulate size (20 nm vs. 80 nm), and concentration in the adhesive (2.5% wt. vs 5.0 % wt.). Two different levels of surface roughness on the bonded area are used; namely, sanding the bond area with G60 or G180 sand paper. Test data and SEM failure mode analysis are provided.


Author(s):  
Sayed A. Nassar ◽  
Marcello Tardito ◽  
Giovanni Belingardi

This study investigates the effect of the rate of autoclave heating and cooling on the performance of bonded lightweight material single lap joints (SLJ) after they have been heat cycled at high relative humidity. Two different temperature ramp rates are used for the autoclave bonding of test joints. Joint performance is assessed in terms of the load transfer capacity (LTC) and the corresponding failure mode in a tensile-shear test. Three different combinations of Aluminium and Magnesium adherends are used in test samples using aliphatic polyether (polyurethane) film adhesive. The effect of heating rate on the peel strength of cured adhesive is also investigated. Data analysis and discussion are provided.


Author(s):  
Sayed A. Nassar ◽  
Shraddha Jagatap ◽  
Marcello Tardito

This study investigates the effect of cure temperature and pressure on the mechanical performance of autoclave-bonded single lap joints (SLJ). Joint load transfer capacity (LTC) and failure mode analysis are provided. Test joints are made of two polycarbonate lexan adherends that are autoclave-bonded together using aliphatic polyether (Polyurethane) film adhesive (Huntsman PE399). Two levels of cure pressure and cure temperature are investigated, for their effect on joint load transfer capacity and failure. Data analysis and discussion are provided.


Author(s):  
Sayed A. Nassar ◽  
Zhijun Wu ◽  
Kassem Moustafa ◽  
Demetrios Tzelepis

An experimental procedure and test setup are used for investigating effect of using nanoparticle additives to the adhesive on the load transfer capacity (LTC) of bonded magnesium (Mg)–steel (St) single lap joints (SLJ). Investigated variables include the nanopowder material (alumina versus silica), particulate size (20 nm versus 80 nm), and concentration in the adhesive (2.5 wt.% versus 5.0 wt.%). Two different levels of surface roughness on the bonded area are used, namely, sanding the bond area with G60 or G180 sand paper. Test data and scanning electron microscopy (SEM) failure mode analysis are provided.


Author(s):  
Kaori Sakai ◽  
Sayed A. Nassar

In this experimental study, both environmental effects and various joining methods are investigated for their impact on the static and dynamic performance of multi-material lightweight single lap joints (SLJ). Adherends are conveniently divided into either composite-based or steel-based lightweight materials that include glass fiber reinforced polymer (GFRP), steel (St), aluminum (Al), or magnesium (Mg). A commercially available adhesive is selected for bonded-only and hybrid bonded-and-bolted joints. Changes in joint static load transfer capacity (LTC) and durability life are investigated for bonded-only, bolted-only, and hybrid bonded-and-bolted joints. Cyclic temperature profile fluctuates between 20° C and 80° C at a constant relative humidity (RH) level of either 20 % or 85 %. Effect on durability life is also studied under a cyclic load that fluctuates between 67.5 % and 75 % of the static load transfer capacity at ambient condition. Detailed discussion of the results, observations, and conclusions are presented in this paper.


Author(s):  
Sayed A. Nassar ◽  
Kaori Sakai

This experimental study investigates the effect of environmental loading and joining methods on the static and dynamic performance of lightweight multimaterial single-lap joints (SLJ). Joint adherend material combinations are divided into two groups; namely, composite-based and steel-based materials that include glass fiber reinforced polymer (GFRP), steel (St), aluminum (Al), and magnesium (Mg). A commercially available adhesive is selected for the study. Investigated joining methods include bonding-only, bolting-only, and hybrid bonding-and-bolting. Static performance is assessed by the load transfer capacity (LTC) of SLJ after they have been subjected to heat cycling at ambient level of relative humidity, or after heat cycling at high relative humidity. Dynamic performance is measured by durability life (in cycles) of SLJ test samples under a fixed dynamic load ratio in a tensile–tensile fatigue test, after they have been subjected to heat cycling and humidity. The cyclic test load fluctuated between 67.5% and 75% of the static LTC at ambient condition. Sample finding includes the significant effect of heat cycling at an ambient humidity level; it has tripled the LTC of bonded-only composite-to-composite SLJ, relative to their baseline LTC at ambient conditions. Detailed discussion of the results, observations, and conclusions are presented in this paper.


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