Joining of hybrid semi-finished products from sheet metal by orbital forming

Contrary demands like a reduction of carbon dioxide emissions and an increase in functionality are facing the manufacturing industry with growing challenges. When processing functional components, like synchronizer rings, conventional process chains, like shearing and subsequent joining, are reaching their limits due to an increased complexity of the components and a lack in efficiency, referring to the long process time. To meet these challenges, the strategy of lightweight construction combines the application of lightweight materials with efficient manufacturing processes and an innovative product design. One possibility within lightweight construction is the utilization of load-adapted hybrid components, featuring different material strength classes. In previous research, the process of orbital forming is used to manufacture semi-finished products with a varying thickness profile due to the specific radial material flow. This material flow should now be used to realize a permanent joint between materials of two different strength levels. Therefore, the process of orbital forming is modified to manufacture hybrid semi-finished products from a dual-phase steel DP600 and a naturally rigid aluminum alloy EN AW 5754, both with an initial thickness of 2.0 mm. Different joint geometries are cut by laser into a steel ring and the part is coaxially positioned around a basic aluminum disc inside a die and subsequently formed. The joint is investigated regarding the geometrical and mechanical properties, comparing a radial cross-section and the micro hardness distribution. In order to reveal the potential of orbital forming for a combined forming and joining operation, the axial as well as the peeling strength of the multi-material components are investigated and evaluated.

Integrating Electronics to Textiles by Ultrasonic Welding for Cable-Driven Applications for Smart Textiles

The connection between flexible textiles and stiff electronic components has always been structurally weak and a limiting factor in the establishment of smart textiles in our everyday life. This paper focuses on the formation of reliable connections between conductive textiles and conventional litz wires using ultrasonic welding. The paper offers a promising approach to solving this problem. The electrical and mechanical performance of the samples were investigated after 15 and 30 wash-and-dry cycles in a laundry machine. Here the contact resistances and their peeling strength were measured. Furthermore, their connection properties were analysed in microsections. The resistance of the joints increased more than 300%, because the silver-coated wires suffered under the laundry cycles. Meanwhile, the mechanical strength during the peeling test decreased by only about 20% after 15 cycles and remained the same after 30 cycles. The good results obtained in this study suggest that ultrasonic welding offers a useful approach to the connection of textile electronics to conductive wires and to the manufacture of smart textiles.

Pengaruh Variasi Bio Based Adhesive terhadap Kekuatan Peeling dan Shearing Kayu Pinus pada Adhesive Joint

The methods of joining engineering materials using adhesives is mostly implemented by using synthetic adhesives from non-renewable sources. Even though it has good joining performance, its poisonous nature and difficult to decompose naturally makes the adhesive needs to seek alternatives that are more environmentally friendly. Another reason is to support FAO campaigns for the use of environmentally friendly and biodegradable materials. One that has the potential to replace synthetic one is adhesives from natural sources such as gum rubber, jackfruit, and breadfruit. Because each natural sap has a different composition, the adhesive strength will also be different. Therefore it is necessary to examine the adhesive strength of each of these natural gums. In this research, natural adhesives (gums) and synthetic adhesives were used to joint pine wood as a test specimen. After joining, peeling and shearing tests on the specimens were carried out so that the mechanical strength of the joints for each adhesive variation was recognized. Fracture analysis was then performed to analyze the mechanism of joint failure for each adhesive variation. From this research, the highest peeling strength was obtained from rubber tree sap of 0.15 MPa, while the highest shearing strength was also obtained for rubber sap of 0.68 MPa.

Effect of 2-phenoxyethanol pre-treatment on structure and adhesion properties of thermotropic liquid crystal polyarylate fibers

This study investigated the surface modification of thermotropic liquid crystal polyarylate (TLCP) fibers by 2-phenoxyethanol pre-treatment, specifically, whether it enhanced their interfacial adhesive properties. The surface chemical compositions and microstructures of both control and 2-phenoxyethanol pre-treated TLCP fibers were characterized by X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. Furthermore, thermal, dyeing, and adhesion properties of both control and 2-phenoxyethanol pre-treated fibers were compared by thermogravimetric analysis, colorimetry, and universal material testing system, respectively. The results indicated that 2-phenoxyethanol pre-treatment increased the surface-anchored oxygen atom amount: the oxygen to carbon atomic ratio at the surface of the TLCP fibers increased from 0.17 to 0.22. However, 2-phenoxyethanol pre-treatment showed almost no effect on the thermal stability and mechanical properties of the TLCP fibers. The peeling strength of the 2-phenoxyethanol pre-treated TLCP fabric was around twice that of the control TLCP fabric.

Detection and Test of Rind-Pith Adhesive Strength of Corn Stalks

HighlightsA detection clamp for the rind-pith adhesive strength of corn stalks based on peeling method was designed.A rind-pith adhesive strength detection method was proposed taking average peeling strength as the test index.The characteristics of rind-pith adhesive strength were analyzed, and a mathematical model between average peeling strength and influencing factors was established.Abstract. Rind-pith separation of corn stalks is one of the effective measures for realizing high-value utilization of stalks. Therefore, it is necessary to study rind-pith adhesive strength of stalks and its influencing factors to determine effective separation methods. In this study, a peeling method was put forward and single factor and multi-factor tests were carried out to explore the rind-pith adhesive strength. The analysis of single factor tests showed that sampling location, moisture content, and peeling speed were all significant on the average rind-pith peeling strength and the Fp = 25.70 > F0.05 (4, 20) = 2.87, Fm = 112.46 > F0.05 (4, 20) = 2.87 and Fs = 231.21 > F0.05 (6, 28) = 2.45. The mathematical model between average peeling strength and influencing factors was established through multi-factor tests. The model was analyzed and optimized, and the significance sequence of influencing factors is sampling location > moisture content > peeling speed, and the effect of interaction between moisture content and sampling location was significant (P<0.05). It can be concluded that the rind-pith peeling strengths of internode sections among 1st-7th internodes of corn stalks were 360.09-450.01 N/m, which are smaller and more favorable for mechanical separation for stalks with moisture content of 15%-20% and at peeling speed of 30-40 mm/min. The results of this study may provide a theoretical reference for the modeling of corn stalks and the subsequent simulation and optimization of rind-pith separation machines. Keywords: Average peeling strength, Adhesive strength, Corn stalks, Rind-pith Separation.

Effect of alkali treatment on adhesion of thermoplastic polyurethane elastomer/polyester inter-ply hybrid composites

Purpose The purpose of this paper is to investigate the effects of alkali treatment on adhesion of industrial thermoplastic polyurethane elastomer (TPU)/polyester woven fabric inter-ply hybrid composites. Design/methodology/approach Inter-ply hybrid composites were exposed to varying concentration of sodium hydroxide at different temperature and time and their mechanical properties including differential scanning calorimetry, scanning electron microscope, tensile and peeling strength evaluated to determine optimal treatment parameters. Findings Modified polyester fabrics treated with alkali had higher tensile and peeling strengths. Accordingly, alkali treatment roughened the surface of polyester fabric, decreasing warp and weft densities, thus increasing fiber surface energy. The fabric had the highest peeling strength of 3.23 N/mm at treatment of 25% concentration of sodium hydroxide (NaOH). Short-term exposure to ultraviolet had little effect on interfacial adhesion of alkali-treated conveyor belt. Research limitations/implications Polyester fabric, applied in reinforcing industrial conveyor belts, is never degreased, roughened, sensitized or activated. In this paper, one-step treatment of polyester fabric was performed to increase its adhesion with polyester inter-ply hybrid composites, providing a reference for practical industrial application. Practical implications The method developed in this research is simple and provides a solution to improving the interfacial adhesion of TPU/polyester conveyor belt. Originality/value The novel alkali treatment technology has many applications in the interfacial performance of composite materials.