INVESTIGATION OF MECHANICAL PROPERTIES OF PIPES WITH BUTT CURVED LAP JOINTS SUBJECTED TO TORSION

2021 ◽  
Vol 8 (18) ◽  
pp. 121-132
Author(s):  
Cüneyt YETKİN ◽  
Şerif ÇİTİL ◽  
Ali İhsan KAYA
Keyword(s):  
Mechanical Properties ◽  
Lap Joints ◽  
Numerical Control ◽  
Three Dimensions ◽  
Galvanized Steel ◽  
Male And Female ◽  
Steel Pipes ◽  
Pipe Joints ◽  
Structural Adhesive ◽  
Validation Experiments

In this study, the mechanical properties of steel pipe joints bonded with an acrylic adhesive under torsion were investigated by considering different overlap lengths and curvilinear radii. For this purpose, St-37 galvanized steel pipes with ØD = 21.3 mm outer and Ød = 15.9 mm inner diameters were modeled in three dimensions by creating 8, 10, 12 mm overlapping lengths in male and female form and 30, 40 and 50 mm curvilinear radii on the forehead regions. Numerical analyzes of the created models were performed in the ANSYS Workbench program, and samples with an overlap length of 10 mm were prepared on the CNC (Computer Numerical Control) bench to verify the numerical analysis. The prepared male and female specimens were joined using an acrylic-based DP810 structural adhesive resistant to humid environments, curable at room temperature, and validation experiments were carried out. After the study, obtained numerical and experimental data showed that pipe lap joints subjected to torsional moment with the same lap length but different curvilinear radius have been observed to vary significantly in the amount of load they carry. In addition, as the overlap length increased, the amount of load they carried increased. Also, in this study was compared by performing stress analyzes according to the overlap length and radii of curvature.

Influence of Heat Input on Mechanical Properties and Microstructure of Laser Welded Dissimilar Galvanized Steel-Aluminum Joints

2018 ◽  
Author(s):  
Celalettin Yuce ◽  
Fatih Karpat ◽  
Nurettin Yavuz
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Penetration Depth ◽  
Heat Input ◽  
Lap Joints ◽  
Galvanized Steel ◽  
Tensile Shear ◽  
Fiber Laser Welding ◽  
Dissimilar Joints ◽  
Weld Width

The hybrid structures of aluminum-steel have been increasingly used for body-in-white constructions in order to reduce weight and green gas emissions. Obtaining acceptable joints between steel and aluminum required a better understanding of welding metallurgy and their effects on the resultant mechanical properties as well as the microstructure of the joints. In this research, the fiber laser welding of zero-gap galvanized steel and aluminum alloy in an overlapped configuration was carried out. The influence of heat input on the weld bead dimension, microstructural and mechanical properties of the joints was studied. A detailed study was conducted on the effects of the heat input on the penetration depth, weld width and microstructure of the laser welded dissimilar joints by means of an optical microscopy. A scanning electron microscopy with energy dispersive spectroscopy was carried out to determine the atomic percent of the elements for intermetallic compounds (IMC) occurred at the interface of the aluminum and steel. Microhardness measurement and tensile shear tests were conducted to evaluate the mechanical properties of the galvanized steel to aluminum lap joints. The experimental results showed that the penetration depth and weld width increased with the increase of heat input level. However, in order to limit IMC layer thickness and hardness at the surface of the weld seam and aluminum alloy, iron to aluminum dilution should be restricted by limiting the penetration depth. At lower heat input levels, less brittle IMC formation was formed. Consequently, with limited penetration depths at low heat input levels, up to 520 N tensile shear load achieved, with failures located in the interface of the joints.

scholarly journals Experimental Study of the Influence of the Surface Preparation on the Fatigue Behavior of Polyamide Single Lap Joints

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1008
Author(s):  
Francesco Musiari ◽  
Fabrizio Moroni
Keyword(s):  
Experimental Study ◽  
Fatigue Behavior ◽  
Atmospheric Pressure Plasma ◽  
Surface Preparation ◽  
Lap Joints ◽  
Polymeric Surfaces ◽  
Adhesively Bonded Joints ◽  
Single Lap Joints ◽  
Number Of Cycles ◽  
Structural Adhesive

The low quality of adhesion performance on polymeric surfaces has forced the development of specific pretreatments able to toughen the interface between substrate and adhesive. Among these methods, atmospheric pressure plasma treatment (APPT) appears particularly suitable for its environmental compatibility and its effectiveness in altering the chemical state of the surface. In this work, an experimental study on adhesively bonded joints realized using polyamide as substrates and polyurethane as the structural adhesive was carried out with the intent to characterize their fatigue behavior, which represents a key issue of such joints during their working life. The single lap joint (SLJ) geometry was chosen and several surface pretreatments were compared with each other: degreasing, abrasion (alone and followed by APPT) and finally APPT. The results show that the abrasion combined with APPT presents the most promising behavior, which appears consistent with the higher percentage of life spent for crack propagation found by means of DIC on this class of joints with respect to the others. APPT alone confers a good fatigue resistance with respect to the simple abrasion, especially at a low number of cycles to failure.

scholarly journals Strength and Failure Mechanism of Composite-Steel Adhesive Bond Single Lap Joints

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Kai Wei ◽  
Yiwei Chen ◽  
Maojun Li ◽  
Xujing Yang
Keyword(s):  
Failure Mechanism ◽  
Shear Failure ◽  
Failure Load ◽  
Lap Joints ◽  
Adhesive Joints ◽  
Adhesive Failure ◽  
Interface Failure ◽  
Element Analysis ◽  
Single Lap Joints ◽  
Structural Adhesive

Carbon fiber-reinforced plastics- (CFRP-) steel single lap joints with regard to tensile loading with two levels of adhesives and four levels of overlap lengths were experimentally analyzed and numerically simulated. Both joint strength and failure mechanism were found to be highly dependent on adhesive type and overlap length. Joints with 7779 structural adhesive were more ductile and produced about 2-3 kN higher failure load than MA830 structural adhesive. Failure load with the two adhesives increased about 147 N and 176 N, respectively, with increasing 1 mm of the overlap length. Cohesion failure was observed in both types of adhesive joints. As the overlap length increased, interface failure appeared solely on the edge of the overlap in 7779 adhesive joints. Finite element analysis (FEA) results revealed that peel and shear stress distributions were nonuniform, which were less severe as overlap length increased. Severe stress concentration was observed on the overlap edge, and shear failure of the adhesive was the main reason for the adhesive failure.

Tensile shear strength of UF- and MUF-bonded veneer related to data of adhesives and cell walls measured by nanoindentation

Holzforschung ◽  
2010 ◽  
Vol 64 (3) ◽  
Author(s):  
Frank Stöckel ◽  
Johannes Konnerth ◽  
Wolfgang Kantner ◽  
Johann Moser ◽  
Wolfgang Gindl
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Bond Strength ◽  
Cell Walls ◽  
Urea Formaldehyde ◽  
Lap Joints ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Interphase Cell ◽  
Cure Time

Abstract The tensile shear strength of veneer lap joints was characterised. The joints were produced with an Automated Bonding Evaluation System (ABES) using urea-formaldehyde (UF) as well as melamine-urea-formaldehyde (MUF) adhesive formulated for particleboard production. At a fixed heating temperature of 110°C, a systematic increase in bond strength was observed for both adhesives with increasing cure time. The absolute bond strength was significantly higher for MUF compared to UF. Nanoindentation experiments with the same specimens used for ABES revealed a very hard, stiff and brittle character of the UF resin, whereas the MUF proved significantly less hard and stiff, and less brit-tle. Wood cell walls in contact with adhesive, i.e., where adhesive penetration into the cell wall was assumed, showed significantly altered mechanical properties. Such cell walls were harder, stiffer and more brittle than unaffected reference cell walls. These effects were slightly more pronounced for UF than for MUF. Comparing UF and MUF, the micro-mechanical properties of cured adhesive and interphase cell walls confirm earlier observations that tougher adhesives can lead to higher macroscopic bond strength. In strong contrast to that, no obvious correlation was found between micromechanical properties and the strong cure time dependence of macroscopic bond strength.

A study on the effect of cooling on microstructure and mechanical properties of friction stir-welded AA5086 aluminum butt and lap joints

2017 ◽  
Vol 233 (6) ◽  
pp. 1156-1165 ◽  
Author(s):  
Adel Sedaghati ◽  
Hamed Bouzary
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Feed Rate ◽  
Rotational Speed ◽  
Lap Joints ◽  
Tensile Behavior ◽  
Water Cooling ◽  
Friction Stir ◽  
Microstructural Behavior ◽  
Constant Feed Rate

In this paper, the effect of water cooling on mechanical properties and microstructure of AA5086 aluminum joints during friction stir welding is investigated. For doing so, the mechanical and microstructural behavior of samples welded both in air and in water was analyzed. Tests were performed involving both butt and lap welds and the results were compared. The effect of rotational speed at constant feed rate of 50 mm/min and changing rotational speed ranging from 250 to 1250 r/min was investigated. The results showed a significant change in the tensile behavior of the butt-welded specimens due to water cooling. In addition, welding was performed at constant spindle speed of 800 r/min and various traverse speeds (25 mm/min to 80 mm/min) to determine the effect of feed rate. The strength increases at first, but then decreases dramatically along with the feed rate which is due to the occurrence of a groove defect. Results showed some generally positive impacts of water cooling which are discussed in terms of tensile results, hardness distributions and microstructure analysis.

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