•Deep learning models were proposed for Al/Cu Laser overlap welding.•Laser welding penetration was predicted based on coaxial weld pool images and photodiode signals.•Multisensor deep learning model ...could predict the penetration depth with a mean absolute error of 0.0302 mm.•The weld depth prediction model can be applied in automotive battery applications.
Al/Cu laser-welded overlap joints, in which weld-penetration depth significantly influences both joint strength and electrical conductivity, are widely applied in automotive battery cells. In this study, a unisensor convolutional neural network (CNN) model that predicts penetration depth using coaxial weld-pool images as input and multisensor CNN models that utilize additional photodiode signals are proposed. The penetration depth was estimated using an optical coherence tomography sensor. The coefficient of determination values for the unisensor and multisensor CNN models were between 0.982 and 0.985, and their mean absolute errors were between 0.0278 and 0.0302 mm. The short-term Fourier transform multisensor model presented the best performance in terms of prediction of penetration depth when applied to the photodiode signal. The proposed prediction models were validated using a gradually varying laser power experiment, which demonstrated the efficacy of this approach and its potential use in automotive applications. Keywords: Laser welding, Al/Cu overlap joint, Penetration-depth estimation, Image sensor, Photodiode, CNN, Deep learning.
Due to the increasing need to use rebar in construction, many efforts have been made to optimize its use. One way to reduce rebar usage is to use welded splice instead of overlap splice. However, the ...Iranian Concrete Code only refers to the welded splice generalities and there are no rules on how to splice. Therefore, the purpose of this study is to investigate the tensile strength of welded splice bars with different configurations. For this purpose, rebars with diameters of 10, 14, 18, 22 and 25 were connected to each other by a variety of discontinuous and continuous overlap patterns by welding with the E6013 electrode. Then the tensile strength of the connected rebars was obtained by tensile test. Then, with Abaqus software and the birth and death method, a variety of splice patterns were modeled and the results were compared with laboratory results. The results show that the optimum welded splice is the model with discontinuous weld with a weld length of 5d.
AA5052 is a widely used aluminum alloy in the automotive industry due to its excellent weldability, mechanical properties, and corrosion resistance. This study aims to optimize the parameters for ...wobbling overlap laser welding of dissimilar thickness aluminum AA5052-H32 sheets. The investigated parameters include laser power, travel speed, focal position, oscillation shape, and oscillation amplitude. The results reveal that the oscillation pattern has a minimal effect on mechanical strength. Additionally, the power intensity range of 13.2–20 J/mm
2
has been identified to ensure that weld efficiency remains above 89.9%. However, considering the significance of the undercut value for achieving a smoother weld line, it is necessary to maintain the oscillation amplitude at a minimum value of 1.5 mm. The microhardness pattern proves to be a valuable method for detecting defects such as underlying porosities and deflection caused by excessive thermal input on the top sheet. The optimized processing parameters for 1–1.5 mm thickness aluminum AA5052-H32 are determined as 2500 W, 5 m/min, 6.0 mm, and 1.5 mm for laser power, travel speed, focal position, and oscillation amplitude, respectively.
Additive manufacturing (AM) has gained significant attention in automotive applications, while the low weldability of AM material poses challenges when assembling AM materials with conventionally ...manufactured materials. This study investigated the laser welding of AM AlSi10Mg and AA1050 sheet metal in an overlap configuration, specifically focusing on the impact of placement configuration of two materials on weld properties. This aims to provide valuable insights for optimizing the localized geometry of AM components to enhance the joint performance. Results showed that positioning AM AlSi10Mg on top leads to a higher weld penetration and higher Si content within the molten pool, especially in the upper sheet. Additionally, weld zone grain structure was greatly influenced by alternating the placement configuration, where welds with AM AlSi10Mg on top exhibiting more equiaxed grains in the weld centre and refined columnar grains near the fusion boundary of upper sheet. Furthermore, significantly reduced weld porosity was determined by positioning AM AlSi10Mg at the bottom (3.2 ± 0.4 %∼7.1 ± 0.9 %) compared to placing it on top (16.9 ± 0.9 %∼20.1 ± 0.9 %) in all scenarios ranging from full penetration to partial penetration. This can be related to the fact that the hydrogen bubbles originating from AM AlSi10Mg experienced a shorter exposure in the molten pool, limiting the merging and growth of small bubbles. However, a slightly lower joint strength was determined in welds with AM AlSi10Mg at the bottom which may be due to the plastic deformation incompatibility between large columnar grains in the fusion zone and the fine grains in the as-printed material.
We prepared overlap soldered joints of high-temperature superconducting tapes, using various materials and preparation conditions. In order to select the joints with optimal performance, we ...correlated their electrical properties (derived from current-voltage curves) with the microstructure of the respective joint cross-section by scanning electron microscopy. With the first group of joints, we focused on the effect of used materials on joint resistivity and critical current, and we found that the dominant role was played by the quality of the internal interfaces of the superconducting tape. Initial joint resistivities ranged in the first group from 41 to 341 nΩ·cm
. The second group of joints underwent a series of thermal cyclings, upon which the initial resistivity range of 35-49 nΩ·cm
broadened to 25-128 nΩ·cm
. After the total of 135 thermal cycles, three out of four joints showed no signs of significant degradation. Within the limit of 100 thermal cycles, reliable soldered joints can be thus prepared, with normalized resistivity not exceeding 1.4 and with normalized critical current above the value of 0.85.
Structures in various industries are exposed to dynamic loads. The dissipative properties of adhesively bonded joints can contribute to the damping of dynamically stressed structures. Dynamic ...hysteresis tests are carried out to determine the damping properties of adhesively bonded overlap joints by varying the geometry and test boundary conditions. The dimensions of the overlap joints are full-scale and thus relevant for steel construction. Based on the results of experimental investigations, a methodology is developed for the analytic determination of the damping properties of adhesively bonded overlap joints for various specimen geometries and stress boundary conditions. For this purpose, dimensional analysis is carried out using the Buckingham Pi Theorem. In summary, it can be stated that the loss factor of adhesively bonded overlap joints investigated within this study is in the range between 0.16 and 0.41. The damping properties can particularly be increased by increasing the adhesive layer thickness and reducing the overlap length. The functional relationships of all the test results shown can be determined by dimensional analysis. An analytical determination of the loss factor considering all identified influencing factors is enabled by derived regression functions with a high coefficient of determination.
From the manufacturing viewpoint, overlapping thin sheets can provide a substantial geometrical improvement in welded hollow sections compared to butt-welded cross-sectional details. However, the ...plate eccentricity and non-penetrating fillet welds make the joints susceptible to fatigue failures under transversal cyclic loads. This work experimentally investigates the fatigue strength of overlap joints prepared with gas metal arc welding in the single-sided fillet weld configuration. Fatigue tests were carried out on the lap joints made of S960 ultra-high-strength steel (UHSS) grade under uniaxial constant amplitude axial loading employing both pulsating tension (applied stress ratio of
R
≈ 0) and pulsating compression (
R
≈ -∞). In addition, the lap joints were prepared with both straight welds (the welds transverse to the loading direction) and inclined welds (the welds with a 30° inclement angle from the transversal direction) to investigate the shear stress effects on the joints’ fatigue performance. Plasma butt-welded samples were tested as a reference join type. For the plasma butt-welded joints, the recommended detail category of FAT71 in the nominal stress system for weld root failures in single-sided butt welds was observed clearly conservative—a mean fatigue strength of Δ
σ
c,50%
= 130 MPa with a fixed slope parameter of
m
= 3 was obtained. Compared to the butt-welded joints, a significant decrease in fatigue strength capacity was found in the lap joint specimens with misalignment factors of
k
m
> 3.0. The failure locations were also different in joints subjected to the tension and compression loads. The shear load did not majorly contribute to the changes in the fatigue strength capacity compared to the joints subjected to the transversal normal stress.
Sheet-coated composite waterproofing (SCCW) have been developed to overcome the natural weakness of singly-ply coating or sheet waterproofing systems for roofing, but there are currently multiple ...types of SCCW joints. Conventional standard tensile strength testing results show that all SCCW joint types seem to pass the minimum requirement and current selection of SCCW type is dictated on the principle of 'higher tensile strength is better', but it has not been experimentally studied as to which type is the optimal to respond to environmental degradation while under the effect of zero-span tensile stress occurring during concrete joint displacement. In this study, five types of SCCW joints were tested: Overlap Bond (OB) type, Overlap Heated-Air Welding (OH) type, Butt Joint I Type (BI), Butt Joint T Type (BT), and Butt Joint Separation Movement Type (BS). These types of joint designs were subjected to Alkali, NaCl, and H
SO
exposure, and temperature change (60 °C and -20 °C) for determining changes to tensile strength in the joint section. Tensile strength change results are compared to joint displacement resistance test results of specimens that were treated with chemical and temperature degradation. With the exception of chemical exposure conditioning, the Overlap type joints generally had higher tensile strength compared to the butt joint types, but joint displacement test results showed the opposite results, suggesting that complex joints found in SCCW require new evaluation method for quality assessment.
This paper reports the experimental results of a study investigating the effect of adhesive joint end shapes on the load-bearing capacity of carbon fibre-reinforce polymer (CFRP) and steel bonded ...joints. In the study, samples with new proprietary types of CFRP strip ends were examined. All samples were subjected to tensile quasi-static loading with a load rate of 1.5 mm/min. A total of 60 samples with CFRP/steel single overlap joints were tested to determine their ultimate load-bearing capacity, effective bond length and failure modes for the above variables. 8 joint end shapes of normal CFRP modulus with three lengths of CFRP overlap and one CFRP cross section (20 x 1.4 mm) were used in this study. Laboratory test results showed that joint end shape has visible effect on the load capacity of the CFRP/steel bonded joints. The load-bearing capacity of the samples with a regular joint end was up to 28 % lower than that of the samples with a plan-shaped end and 30 % lower than that of the samples with a chamfered end with adhesive outflow. The differences in the results decreased with increase in joint end length towards the effective end length.
In this study, we improved twin-box joint, for smaller volume, lower resistance and more uniform tension insulators, a sub-cable overlap joint design was proposed. For sub-cable overlap joint ...resistance calculation, a model for joint resistance calculation was developed, the resistance of twin-box joint was calculated 0.201 nΩ, which was close to the test resistance, thus the model was acceptable, and the resistance of sub-cable overlap joint was calculated 0.0776 nΩ. A model was developed for AC losses calculation of two type joints, AC losses of sub-cable overlap joint were smaller than that of twin-box joint. Thermo-hydraulic simulations of the respective busbar cables with twin-box joints and sub-cable overlap joints were carried out with THEA code in 15 MA reference scenario, the temperature margin of busbar with sub-cable overlap joints was high than that with twin-box joints, and the temperature rise added by sub-cable overlap joints was lower than that value added by twin-box joints.
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•Improved twin-box joint, for smaller volume, lower resistance and more uniform tension insulators, a sub-cable overlap joint design was proposed.•Developed a model to calculate resistance of twin-box joint and sub-cable overlap joint.•Developed a model to calculated AC losses of twin-box joint and sub-cable overlap joint.•Analyzed busbar cables with twin-box joints and sub-cable overlap joints in 15 MA reference scenario, calculated temperature margins of cables with two type joints, and calculated temperature rises of cables added by two type joints.
Typically, the superconducting busbar of TOKAMAK feeder system is divided into different segments, which are connected by superconducting joints. ASIPP (Institute of Plasma Physics, Chinese Academy of Sciences) feeder team has improved the twin-box for ITER (International Thermonuclear Experimental Reactor) feeder systems. In the twin-box joint, the two cables were connected by two compressed against copper soles, and the pure indium was used as solder. For superconducting joint improvement, ASIPP feeder teams design a sub-cable overlap joint with smaller volume, lower resistance and more uniform tension insulators. In the sub-cable overlap joint, the cable is untwisted at the sub-cable stage, and sub-cables of two cables are connected by indium-coated copper soles. A brief analysis including resistance, AC losses and temperature rise produced by joints of the respective busbar with twin-box and sub-cable overlap joints was carried out in ITER 15 MA plasma current reference scenario. The sub-cable overlap joint has smaller resistance of 0.0776 nΩ and lower AC losses of 5.95 W than twin-box joint with 0.201 nΩ resistance and 1.182 W AC losses. The design length of sub-cable overlap joint is 300 mm, shorter than twin-box joint length of 450 mm. The cylindrical shape sub-cable overlap joint makes tension insulators much more uniform than that in twin-box joint.
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