Effect of Aging Time at High Temperature on the Shear Strength of Adhesively Bonded Aluminum Composite Foam Joints
TL;DR: In this paper, the shear strength behavior of adhesively bonded joints, made of aluminum composite foams subjected to high-temperature processes, has been investigated, and the aging at 200 oC was performed on the samples for 15, 30, 45, 60 minutes.
Abstract: In this study, the shear strength behavior of adhesively bonded joints, made of aluminum composite foams subjected to high-temperature processes, has been investigated. Aluminum composite foam and solid aluminum blocks were used to form single lap joints and as the binder, a methacrylate-based structural adhesive has been selected. Foam-foam and solid-foam joints were formed and cured at room temperature for 24 hours. After curing process, aging at 200 oC was performed on the samples for 15, 30, 45, 60 minutes. The aged samples were subjected to lap shear testing for adhesively bonded metals and the influences of aging duration on joint strength and failure type were investigated.As a result, lower strengths were obtained in all samples that aged under high temperature compared to non-aged samples. After the application of short-term (15-30 min) aging processes on samples, it is observed that they have joint strength values about 50% of the joint strength of non-aged samples. However, strength val...
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TL;DR: In this article, the effect of humidity and temperature in the mechanical and thermal properties of two polyurethane adhesives joints was evaluated by means of two devices specially developed for the study, durability and heat aging tests were performed.
20 citations
TL;DR: In this paper, the effect of bending angle, face sheet thickness and core thickness on the springback behavior of fiber metal laminates was investigated and the results showed that the amount of springback in the FML specimen increased as the bending angle increased.
Abstract: Fiber metal laminates (FMLs) are a kind of hybrid composite material that consist of metal sheets and fiber-reinforced composite layers. The use of FMLs has been particularly increasing in the production of aircraft bodies. However, the springback behavior that occurs during the formation of FML parts has a negative impact on the form of the final product. In the present study, FMLs were manufactured by combining aluminum 5754-H22 sheets and carbon fiber-reinforced plastic sheets by using adhesive. A set of experiments were performed to determine the effect of bending angle, face sheet thickness and core thickness on the springback behavior of FMLs. The results showed that the amount of springback in the FML specimen increased as the bending angle increased. It was found that when the thickness of the face sheet increased, the amount of springback in FML specimens was higher in all bending angles. In addition, the amount of springback in FML specimens decreased as core thickness increased.
4 citations
01 Jan 2003
TL;DR: In this paper, the effects of surface pretreatment and moisture in both durability and fracture path of single lap shear joints were investigated using a DGEBA-based epoxy resin cured by a modified dicyandiamide.
Abstract: Adhesively bonded aluminium single lap shear joints were tested to failure under fatigue loading to ascertain the effects of surface pretreatment and moisture in both durability and fracture path. The aluminium substrate used was AA5754 with and without a silicon based pretreatment. The adhesive used was a commercially available DGEBA based epoxy resin cured by a modified dicyandiamide. Fatigue tests were performed at 20Hz using an R-ratio of 0.1. To monitor the effects of moisture, tests were performed in a chamber that generated 96% relative humidity (r.h.). S-N curves were generated and several microscopic and surface analysis techniques were employed to characterise the failure mode of the joints. The techniques included simple visual observation, SEM, TEM and high magnification video recordings. The fatigue performance of pretreated and untreated joints were similar when tested in air, but the performance of the untreated joints was greatly reduced when tested in 96% r.h. The differences in fatigue performance between untreated and pretreated joints in 96% r.h. are thought to be due to differences in failure mode of the joints arising from the improved interfacial bonding between the pretreatment and the adhesive. Pretreated joints failed predominantly cohesively through the adhesive, while untreated joints failed mainly interfacially at the adhesive/aluminium interface. High magnification video recordings have also shown that the adhesive fillet is a significant factor in determining the life of a single lap joint.
1 citations
27 Jan 2020
TL;DR: Ayrica, T1 (saat yonunun tersinde) bukme yonundeki sandvic kompozit levhalarin 75° ve 90° bakme acilarindaki testlerinde aluminyum ve karbon elyaf plakalar arasinda acilmalar gorulurken.
Abstract: Bu calismada, aluminyum-karbon elyaf sandvic levhalarin V bukme operasyonu neticesinde olusan geri esneme davranisi deneysel olarak incelenmistir. Bukme yonunun geri esneme davranisi uzerine olan etkisini incelemek amaciyla farkli bukme yonlerindeki sandvic kompozit levhalar 15°, 30°, 45°, 60°, 75° ve 90° bukme acilarinda sekillendirilmistir. Farkli bukme yonlerinde sekillendirilen sandvic kompozit levhalarda meydana gelen geri esneme degerlerinin birbirine cok yakin oldugu tespit edilmistir. Ayrica, T1 (saat yonunun tersinde) bukme yonundeki sandvic kompozit levhalarin 75° ve 90° bukme acilarindaki testlerinde aluminyum ve karbon elyaf plakalar arasinda acilmalar gorulurken, T2 (saat yonunde) bukme yonundeki sandvic kompozit levhalarin 75° ve 90° bukme acilarinda ise dis taraftaki aluminyum sac levhalarda yirtilmalar olusmustur.
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...3 mm yapıştırıcı kalınlığı elde edilmiştir [21]....
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TL;DR: In this paper , the authors evaluated the thermal aging properties of a new room temperature cured structural adhesive and obtained the generalized curve of polymers aging for a specific time at a specific temperature.
Abstract: This study mainly evaluates the thermal aging properties of a new room temperature cured structural adhesive. Multiple adhesive specimens were thermal aged at 80℃, 100℃, 120℃ and 140℃, respectively, and subjected to the dynamic mechanical analysis (DMA) at different temperatures and frequencies. According to the results of DMA and thermodynamic analysis, the performance of the adhesive changes little after aging at 80℃, 100℃ and 120℃ for 30 days. However, the adhesive performance became unstable at 140℃, and deteriorated rapidly with the extension of aging time. Hence, this structural adhesive is suitable for the environment below 120℃. In addition, the generalized curve of the structural adhesive aging for 20 days at 100℃ was obtained, following the principles of time-temperature equivalence superposition and time-aging time equivalence superposition. The test time was shortened significantly. This research provides an accelerated characterization strategy for the long-term mechanical properties of other polymers, making it possible to obtain the generalized curve of polymers aging for a specific time at a specific temperature.
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TL;DR: Porous metals and metallic foams are presently the focus of very active research and development activities as discussed by the authors, with particular emphasis on research presented at the latest International Conference on Porous Metals and Metallic Foams (MetFoam 2007).
Abstract: Porous metals and metallic foams are presently the focus of very active research and development activities. There are currently around 150 institutions working on metallic foams worldwide, most of them focussing on their manufacture and characterisation. Various companies are developing and producing these materials which are now being used in numerous industrial applications such as lightweight structures, biomedical implants, filters, electrodes, catalysts, and heat exchangers. This review summarizes recent developments on these materials, with particular emphasis on research presented at the latest International Conference on Porous Metals and Metallic Foams (MetFoam 2007).
683 citations
TL;DR: In this article, the various processing steps of aluminium foam sandwich (AFS) and the metallurgical processes during foaming, compare the process to alternative ways to manufacture AFS, e.g. by adhesive bonding, and give an overview of the available literature.
Abstract: Sandwich panels consisting of a highly porous aluminium foam core and aluminium alloy face sheets are manufactured by roll-bonding aluminium alloy sheets to a densified mixture of metal powders – usually Al-Si or Al-Si-Cu alloys with 6–8% Si and 3–10% Cu – and titanium hydride, and foaming the resulting three-layer structure by a thermal treatment. We review the various processing steps of aluminium foam sandwich (AFS) and the metallurgical processes during foaming, compare the process to alternative ways to manufacture AFS, e.g. by adhesive bonding, and give an overview of the available literature. Two ways to treat AFS after foaming are presented, namely forging and age-hardening. Some current and potential applications are described and the market potential of AFS is assessed.
231 citations
TL;DR: In this article, the energy absorption capability of the composite structures is much greater than the sum of the energy absorbed by the two components, the foam and the tube, and the results obtained will be presented as quasistatic and dynamic uniaxial compression and quasi-static bending and shear loading.
117 citations
TL;DR: In this article, a brief outline of the factors involved in the search for gas-generating agents offering superior performance for foaming of liquid aluminium alloys is presented, including the kinetic and thermodynamic characteristics of decomposition reactions, the ease of dispersion of the powdered foaming agent in the melt, the nature and likely effect on melt flow, potential reactions between the foaming gas and the melt and the availability, cost and ease of handling of the powder concerned.
103 citations
TL;DR: In this paper, an experimental study on the effect of surface roughness of different adherend material on adhesive bond strength was carried out, and the results showed that there is a clear dependency observed in between the adhesively bond strength and surface roughs of both wood and aluminium adherend joints.
Abstract: In this paper, an experimental study on the effect of surface roughness of different adherend material on adhesive bond strength was carried out. The adherend material used was aluminium AA6061 and wood in the form of sheet, and the adhesive was an epoxy resin. Different surface roughness obtained by mechanical abrasion using an emery paper and sand paper for aluminium and wood adherend samples respectively. Single strap joints were tested at room temperature. Results showed that there is clear dependency observed in between the adhesive bond strength and surface roughness of both wood and aluminium adherend joints. Optimum surface roughness values were obtained in the range of Ra = 1.68 ± 0.14 µm and Ra = 1.64 ± 0.2 µm for the aluminium and wood adherend joints respectively. Surface roughness along with the adhered material parameters should be considered during design stage of adhesively bonded joints.
71 citations