Joint Defects Research Articles

Utilization of Capacitor Bank for Electromagnetic Pulse Crimping

Capacitors play an important role in an electrical system. They have numerous applications in the field of lasers, fast X-ray, neutron sources, electromagnetic pulse generators, electron beam accelerators, plasma generation and electromagnetic welding of materials. One of the applications of high voltage capacitors as energy storage and discharge devices is in the crimping of cables using the electromagnetic pulse forming technique. This research paper investigates the use of a high-voltage energy storage capacitor with a capacitance of 208 microfarads and rated voltage of 44 kV to perform Electromagnetic Pulse Crimping (EMPC) of lugs for 70 mm2 and 120 mm2 cables. The capacitor operates at 12 kV and is discharged to produce a high current that generates a strong magnetic field of up to 20 Tesla, which is utilized for joining the cable conductor and the lug. The study examines the performance of the capacitor under different operating values such as voltage, capacitance, and discharge time and investigates the effect of these parameters on the termination quality. The paper presents the experimental results of the crimping, which include the contact resistance, weld strength, microstructure, and defects of the welded joints. The results indicate that the capacitor-based electromagnetic pulse crimping produces welds with high strength and minimal defects. Additionally, the paper discusses the future scope of research in this area and the potential applications of such capacitors in other welding techniques. The findings of this research paper provide valuable insights for engineers and researchers working in the field of energy storage, high-voltage applications and welding.

Probability of Defects Detection in Welded Joints using the Magnetic Particle Method

The probability of defects detection (POD) is developed as an efficient tool to evaluate the detection capacity of non-destructive testing methods. An experimental study has been carried out applying the magnetic particle test method with an electromagnetic yoke on welded steel joints, which contained surface defects previously characterized in shape, size and location. The test conditions were varied, such as the type of magnetization current, and the type of magnetic particle. The probability of detecting defects in welded joints evaluated by the Hit/miss method increased with the size of the defect, independent of its shape factor. Smaller defects were likely to be detected with dry magnetic particles compared to wet fluorescent ones, a50 (2,118 mm ˂ 2,469 mm), a90 (6,395 mm ˂ 6,77 mm) and a90/95 (12,12 mm ˂ 12,19 mm).

Fatigue load spectrum generation of Indonesian high-speed trains

The high-speed trains designed and constructed in Indonesia will use Aluminum alloy Al 6061-T6 as a structural material. Aluminum alloys are prone to fatigue failure due to the absence of endurance limit of the material, hence fatigue life prediction has to be carried out. Fatigue cracks could initiate at the defects of welded joints. Analyzing the fatigue load spectrum of critical locations in the train structures is crucial to predicting fatigue life. These critical locations are selected from areas with high static stress and stress concentration. The loads are analyzed using the multibody dynamic with rigid body assumptions and track roughness following UIC Standard Code 518. The finite element method is used to calculate the stresses from the loads generated by the multibody dynamic. The load sequence is further analyzed with rainflow counting method, and the load exceedance curve can be constructed. Finally, the Miner Linear Cumulative Damage Model is used to predict fatigue life.

High quality repair of osteochondral defects in rats using the extracellular matrix of antler stem cells.

Cartilage defects are some of the most common causes of arthritis. Cartilage lesions caused by inflammation, trauma or degenerative disease normally result in osteochondral defects. Previous studies have shown that decellularized extracellular matrix (ECM) derived from autologous, allogenic, or xenogeneic mesenchymal stromal cells (MSCs) can effectively restore osteochondral integrity. To determine whether the decellularized ECM of antler reserve mesenchymal cells (RMCs), a xenogeneic material from antler stem cells, is superior to the currently available treatments for osteochondral defects. We isolated the RMCs from a 60-d-old sika deer antler and cultured them in vitro to 70% confluence; 50 mg/mL L-ascorbic acid was then added to the medium to stimulate ECM deposition. Decellularized sheets of adipocyte-derived MSCs (aMSCs) and antlerogenic periosteal cells (another type of antler stem cells) were used as the controls. Three weeks after ascorbic acid stimulation, the ECM sheets were harvested and applied to the osteochondral defects in rat knee joints. The defects were successfully repaired by applying the ECM-sheets. The highest quality of repair was achieved in the RMC-ECM group both in vitro (including cell attachment and proliferation), and in vivo (including the simultaneous regeneration of well-vascularized subchondral bone and avascular articular hyaline cartilage integrated with surrounding native tissues). Notably, the antler-stem-cell-derived ECM (xenogeneic) performed better than the aMSC-ECM (allogenic), while the ECM of the active antler stem cells was superior to that of the quiescent antler stem cells. Decellularized xenogeneic ECM derived from the antler stem cell, particularly the active form (RMC-ECM), can achieve high quality repair/reconstruction of osteochondral defects, suggesting that selection of decellularized ECM for such repair should be focused more on bioactivity rather than kinship.

Research on multi-physical field analysis and assessment technique of virtual connection defects in cluster cable joints based on digital twin technology

As the “blood vessels” and “nerves” of the power grid, cables are important carriers for transmitting electric energy, and their failures will affect the safe and stable operation of the power grid. In this paper, a digital twin model of thermal characteristics is constructed for 10 kV YJV×400 cluster cable and its joint model. Based on the multi-physical field coupling analysis method, the fluid field, temperature field and current-carrying capacity of the cluster cable are analyzed. The temperature rise and airflow distribution characteristics of the joint and its external insulation when the defect of joint false connection occurs are analyzed. Based on the fuzzy analytic hierarchy process (FAHP), weights are assigned to the locations of multiple measurement points of the cable external insulation, and the temperature distribution of each measurement point is combined with the digital twin technology to calculate the hot spot temperature of the cable, so as to assess the defects of the joints of the cables. The digital twin platform is used for real-time monitoring of cable status and assessment of defects. The temperature rise experiments of cables under different carrying capacity and joint defects show that this method can accurately and efficiently calculate hot spot temperatures and assess defects of joints in cluster cables.

Evaluation of Welded Lap Joints Using Ultrasonic Guided Waves.

Welded lap joints play a vital role in a wide range of engineering structures such as pipelines, storage tanks, pressure vessels, and ship hulls. This study aims to investigate the propagation of ultrasonic guided waves in steel welded lap joints for the baseline-free inspection of joint defects using the mode conversion of Lamb waves. The finite element method was used to simulate a single lap joint with common defects such as corrosion and disbonding. To identify the propagating wave modes, a wavenumber-frequency analysis was conducted using the 2D fast Fourier transform. The power loss of the transmitted modes was also determined to identify damage in the lap joints. The results indicate that the A0 incident in pristine conditions experienced significant transmission losses of about 9.5 dB compared to an attenuation of 2.8 dB for the S0 incident. The presence of corrosion was found to reduce these transmission losses by more than 28%. In contrast, introducing disbonding in the lap joint increased the transmission loss of the S0 incident, while a negligible loss was observed for the A0 incident. The mode-converted S0 (MC-S) and mode-converted A0 (MC-A0) incidents were found to exhibit a unique sensitivity to the presence of corrosion and disbonding. The results indicate that MC-S0 and MC-A0 as well as Lamb mode incidents interact differently in terms of corrosion and disbonding, providing a means to identify damage without relying on baseline signals.

Comparison of the Efficacy of Human Umbilical Cord-Derived and Bone Marrow Aspirate Concentrate Mesenchymal Stem Cells for Cartilage Repair Defects of the Knee via Arthroscopic Implementation on Scaffolds in a Retrospective Study.

Injuries to the articular cartilage of the human knee joint, commonly resulting from trauma, inflammation, or age- and activity-related wear and tear, have significant implications, primarily leading to osteoarthritis (OA). Conservative treatments for such injuries often yield suboptimal clinical outcomes. Surgical interventions using current methods may not consistently provide satisfactory results, largely due to the formation of low-quality scar tissue lacking the biomechanical properties of hyaline cartilage. In this retrospective study, we compared the results of two promising methods for regenerating cartilage defects in the knee joints using scaffolds soaked with stem cells of different origins: bone marrow aspirate concentrate mesenchymal stem cells (BMAC-MSCs) and human umbilical cord-derived mesenchymal stem cells (hUCB-MSCs). We evaluated 39 patients (39 knees, hUCB-MSCs: 20 knees, BMAC: 19 knees) at the 12-month follow-up using VAS, KOOS, Lysholm scales and radiologically with M-MOCART 2.0 score. The analysis demonstrated substantial overall improvement in both groups, notably reflected in enhanced quality of life for the patients. Interestingly, the final scores in the hUCB-MSCs group were comparable to those in the BMAC-MSCs group, with no statistically significant differences observed, despite variations in preoperative age and lesion size. Notably, the hUCB-MSCs group consisted of significantly older individuals with larger lesion sizes. Both procedures were found to be safe, and improvement was observed in both groups, which holds promise for future clinical investigations.

Molecular co-assembled strategy tuning protein conformation for cartilage regeneration.

The assembly of oligopeptide and polypeptide molecules can reconstruct various ordered advanced structures through intermolecular interactions to achieve protein-like biofunction. Here, we develop a "molecular velcro"-inspired peptide and gelatin co-assembly strategy, in which amphiphilic supramolecular tripeptides are attached to the molecular chain of gelatin methacryloyl via intra-/intermolecular interactions. We perform molecular docking and dynamics simulations to demonstrate the feasibility of this strategy and reveal the advanced structural transition of the co-assembled hydrogel, which brings more ordered β-sheet content and 10-fold or more compressive strength improvement. We conduct transcriptome analysis to reveal the role of co-assembled hydrogel in promoting cell proliferation and chondrogenic differentiation. Subcutaneous implantation evaluation confirms considerably reduced inflammatory responses and immunogenicity in comparison with type I collagen. We demonstrate that bone mesenchymal stem cells-laden co-assembled hydrogel can be stably fixed in rabbit knee joint defects by photocuring, which significantly facilitates hyaline cartilage regeneration after three months. This co-assembly strategy provides an approach for developing cartilage regenerative biomaterials.

Determination of Joint Defects in Copper Tube Induction Heating Brazing Area Using Infrared Thermal Image Based on CNN Algorithm

Determination of Joint Defects in Copper Tube Induction Heating Brazing Area Using Infrared Thermal Image Based on CNN Algorithm

Сварка деталей из полимерных композиционных материалов на основе термопластов. Часть 4. Методы испытаний и контроля качества сварки деталей из термопластов

This article is a continuation of a series of articles on welding parts made of polymer composite materials based on thermoplastics. In the fourth article in the series, the most common methods of quality control and test of welded joints of products made of polymer composite materials based on thermoplastic binders are considered. Typical defects of welded joints of plastics have been determined. The technologies of destructive and non-destructive inspection of welded joints of plastic products are considered.

APPLICATION OF MACHINE LEARNING FOR RECOGNIZING SURFACE WELDING DEFECTS IN VIDEO SEQUENCES

The paper offers a solution to the problem of detecting and recognizing surface defects in welded joints that appear during tungsten inert gas welding of metal edges. This problem belongs to the machine vision. Welding of stainless-steel edges is carried out automatically on the pipe production line. Therefore, frames of video sequences are investigated. Images of some welding defects are shown in the paper. An algorithm proposed by the authors is used to detect welding defects in the video sequence frames, the efficiency of which has been confirmed experimentally. The problem solution of welding defects recognition is based on the use of traditional machine learning methods: support vector machine and artificial neural network. To build classification models, a labeled dataset containing automatically extracted texture features from the areas of welding defects detected in the video sequences was created. An analysis was performed to identify the strength of the correlation of texture features between each other and the dependent variable in the dataset for dimensionality reduction of the feature vector. The models were trained and tested on datasets with different numbers of features. The quality of the classification models was evaluated based on the accuracy metric values. The best results were achieved by the classifier built using the support vector machine with a chi-square kernel on a training sample with two features. The build models allow automatic recognition of such welding defects as lack of fusion and metal oxidation. The computational experiments with real video sequences obtained with a digital camera confirmed the possibility of using the proposed solution for recognizing surface welding defects in the process of manufacturing stainless steel pipes.

Treatment of cartilage defects in the patellofemoral joint with matrix-associated autologous chondrocyte implantation effectively improves pain, function, and radiological outcomes after 5-7 years.

The aim of the present study was to evaluate midterm outcomes 5-7years after matrix-associated autologous chondrocyte implantation (MACI) in the patellofemoral joint. Twenty-six patients who had undergone MACI using the Novocart® 3D scaffold were prospectively evaluated. Clinical outcomes were determined by measuring the 36-Item Short-Form Health Survey (SF-36) and International Knee Documentation Committee (IKDC) scores and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) values preoperatively and 3, 6, and 12months, and a mean of 6years postoperatively. At the final follow-up, the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score was evaluated. Twenty-two patients with 23 focal cartilage defects (19 patella and four trochlea) were available for the final follow-up. The mean defect size was 4.0 ± 1.9 cm2 (range 2.4-9.4 cm2). All clinical outcome scores improved significantly until 5-7 years after MACI (SF-36 score, 61.2 ± 19.6 to 83.2 ± 11.6; P = 0.001; IKDC score, 47.5 ± 20.6 to 74.7 ± 15.5; P < 0.001; and WOMAC, 29.8 ± 15.7 to 8.2 ± 10.3; P < 0.001). The mean MOCART score was 76.0 ± 11.0 at the final follow-up. Nineteen of the 22 patients (86.4%) were satisfied with the outcomes after 5-7 years and responded that they would undergo the procedure again. MACI in the patellofemoral joint demonstrated good midterm clinical results with a significant reduction in pain, improvement in function, and high patient satisfaction. These clinical findings are supported by radiological evidence from MOCART scores. IV-case series.

A Study on Defect Detection of Dissimilar Joints in Cu-STS Tubes Using Infrared Thermal Imaging of Induction Heating Brazing

We proposed a novel detection method for identifying joint defects in the brazing process between copper tubes and stainless steel using a convolutional neural network (CNN) model. The brazing joints were created using high-frequency induction heating equipment, and infrared thermal imaging cameras were employed to capture the thermal data generated during the jointing process. The experiments involved 15.88 mm diameter copper tubes commonly used in plate heat exchangers, stainless-steel tubes, and filler metal containing 20% Ag. The thermal data were obtained with a resolution of 80 × 80 pixels per frame, resulting in 4796 normal joint data and 5437 defective joint data collected over 100 high-frequency induction-heating brazing experiments. A total of 10,233 thermal imaging data were categorized into 6548 training data, 1638 validation data, and 2047 test data for the development of the predictive model. We designed CNN models with varying hyperparameters, specifically the number of kernel filters and nodes, to evaluate their impact on detection performance. A comparative analysis revealed that a CNN model structure, exhibiting 98.53% accuracy and 99.82% recall on test data, was the most effective. The selected CNN-based defect prediction model demonstrated the potential of using CNN models to discern joint defects in tube configurations that are challenging to identify visually. This study opens avenues for applying CNN-based models for detecting imperfections in complex tube structures.

Multifactor optimization for induction welding of carbon fiber reinforced thermoplastic composites based on response surface methodology

AbstractInduction welding of thermoplastic (CFRP) composites is one of the most promising welding techniques due to its high efficiency, flexibility, and selectivity of the heat area. However, the nonuniformity of the temperature field in the welding area poses a challenge to welding quality. In this paper, a multifactor optimization method devoted to the quality and efficient bonding of carbon fiber‐reinforced polycarbonate (CF/PC) composites was presented. A transient three‐dimensional finite element model was developed and validated to analyze the heating characteristics during the welding process. The mapping relationship between process parameters—equilibrium temperature and relative effective area were established to optimize the weld quality applying the response surface method. The single lap shear experiment was carried out to evaluate the mechanical properties of the welded joints, focusing on micro appearances and welding defects. The results show that the optimal process parameters are a current of 100A and a coil distance from the surface of 3.6 mm. Under the process parameter, the effective welding area is 0.3823 with an error of 4.25%.Highlights The transient three‐dimensional finite element (FE) model was established. The evaluation indicators for welding quality were proposed. The multifactor optimization method for process parameters was developed. The mechanical property and welding defects of welded joints is evaluated.

XLPE cable joint defects measurement method based on point cloud remapping

For the problems of low detection accuracy caused by weak texture and strong reflection on the surface of Cross-linked polyethylene (XLPE) high-voltage cable joint, this paper proposed a joint point cloud remapping and image segmentation method for the cable joint defects measurement, which improved the defects measurement accuracy from the correlation of the disordered point cloud and the salience of defects. Firstly, the discrete noise in the joint point cloud is removed using a modified radius filtering algorithm. Secondly, for the problems of disorderliness and weak association of the cable joint point cloud, we utilized Rodrigues' rotation formula (RRF) to correct the position of the XLPE cable joint point cloud. Then, for the demand of improving feature expression of non-significant defects, a point cloud remapping method is proposed, which remapping insignificant defects point cloud into saliency image for more effective detection. Lastly, an image segmentation method based on 8-neighborhood growth is applied for explicit defects detection, and the detected defects are quantified by the proposed measurement approach. Extensive experiments are conducted on the collected cable joints' point cloud and simulated cable joints' point cloud. With the help of the proposed method, we can achieve the best effects in DE, FR quantitative comparison, and the measurement inaccuracies are less than 4.5%. Experimental results demonstrate that the proposed method enjoys state-of-the-art performance in cable joint defects measurement.

Loss of Axin1 in limb mesenchymal cells leads to multiple synostoses syndrome-like phenotype in mice

&lt;p&gt;Multiple synostoses syndrome (SYNS) is a disease characterized by the fusion of multiple joints. Unfortunately, the underlying and critical signaling pathways of this disorder remain poorly understood. Given the pivotal role of Wnt/��-catenin signaling in skeletal development and the key regulatory effect of Axin1 and Axin2 in the ��-catenin pathway, limb mesenchymal stem cell (MSC) specific &lt;i&gt;Axin1&lt;/i&gt; conditional KO (cKO) mice and &lt;i&gt;Axin1&lt;/i&gt;/&lt;i&gt;Axin2&lt;/i&gt; double KO (dKO) mice were generated to explore their involvement in joint formation. Abnormalities, such as developmental defects in joints and fusions in multiple joint tissues were observed in both &lt;i&gt;Axin1&lt;/i&gt; cKO and &lt;i&gt;Axin1&lt;/i&gt;/&lt;i&gt;Axin2&lt;/i&gt; dKO mice, which resemble to the characteristics of human SYNS disease including synostoses of carpal and tarsal bones, as well as ankylosis of elbow joint and knee joint. Administration of ��-catenin or BMP inhibitor significantly reversed the joint fusion phenotype in &lt;i&gt;Axin1&lt;/i&gt; cKO mice. Our findings suggest that Axin1 plays a key role in joint formation by inhibiting ��-catenin-BMP signaling and could potentially serve as a therapeutic target for SYNS.&lt;/p&gt;

Analyzing Defects in One-Step Double-Acting Friction Stir Welded of Hollow Aluminum Panel: Influence of Travel Speed

This study investigates hollow aluminum panels AA6061 produced through extrusion. The One-Step Double-Acting Friction Stir Welding (ODFSW) technique was used to weld the panels. The tool rotated at 1500 RPM, and the travel speeds were 15 and 30 mm/min. ODFSW is a friction stir welding process that uses two tools moving simultaneously on the top and bottom surfaces of the workpiece. This method offers an environmentally friendly alternative to conventional fusion welding, which requires more energy and generates higher greenhouse gas emissions. The research aims to evaluate the influence of travel speed on weld defects in ODFSW joints, including flash, surface surface grooves, and surface roughness. The results show that while higher travel speeds can improve weld quality. It also poses challenges in heat management and material mixing, leading to larger defects on the bottom side due to uneven heat distribution. At a travel speed of 15 mm/min, defects such as long flash, significant surface surface grooves, high surface roughness, and exit holes were observed, mainly due to excessive welding temperatures and extended contact times. In contrast, at 30 mm/min, although surface surface grooves on the top side were reduced, defects on the bottom side increased, along with higher surface roughness.

YOLO algorithm with hybrid attention feature pyramid network for solder joint defect detection

YOLO algorithm with hybrid attention feature pyramid network for solder joint defect detection

Inspection of Welded Joints of Boiler Tubes Using Visual and Penetration NDT Methods

The article discusses weld joint defects that were observed during boiler overhaul during shutdown. Visual methods as well as penetration methods were used in the project to check welds. These are mainly the welds of membrane wall pipes and also the welds of pipes for the supply of combustion air. Found weld defects are described and also their photo documentation is included. The aim of this article is to point out recurring defects in welds, especially when replacing membrane wall panels in boilers, and thereby contribute to the prevention of these inhomogeneities.

Influence of scandium interlayer on the mechanical and metallurgical characteristics of friction stir welded AA1200-H14/ Sc/AA6061-T6

The present investigation observed the friction stir welding (FSW) of joints made from the interfacial layered dissimilar AA1200-H14 and AA6061-T6 using scandium about the UTS, frictional heat, and metallurgical properties. The experimental examination is carried out utilising a three-level, three factors, Box-Behnken Design matrix (17 tests) in response surface approach, with the welding speed (WS), axial force (AF), and tool rotation speed (TRS) as the stated input parameters. Analysis of variance (ANOVA) was used to evaluate the model’s dependability. Macroscopic and microscopic joint defects, as well as the alloy intermixture, have been found using optical microscopy and SEM. The SEM microstructural study exhibited that the generated grains are fine and equiaxed. The optimal WS (50 mm min−1), A−1F−1 (10 kN) and TRS (1750 rpm) settings produced the maximum terminal tensile strength (200.182 MPa) and perfect frictional heat observations. The inclusion of scandium interlayer as well as optimised parameters improved the joint’s mechanical characteristics and produced a fine-grained microstructure.