Search Results (47)

This paper presents the possibilities of using steel cord from car tires as a structural concrete reinforcement obtained after initial mechanical treatment. The steel wire constituting tire reinforcement after mechanical separation from rubber is not further processed and, in the form partially contaminated with rubber, is stored in landfills. Further processing is usually not economically justified. The purpose of the work is to determine the physical properties of fiber concrete, made of ordinary concrete with the addition of steel fibers recovered from tires, obtained in the process of relatively easy recycling. The work is mainly experimental. The literature review presents the basics of the current state of knowledge regarding the methods of making and testing elements made of fiber-reinforced concrete. In the next part, the authors’ own research and results of testing fiber-reinforced concrete with wires after pre-cleaning are shown. Chapter five summarizes the results of research and juxtaposes the most important observations that can be used for the practical use of fibers obtained in a simple recycling technology. The utilitarian value of the work is to show the practical possibilities of recovery (recycling) of used tires, in particular for the fiber-reinforcement of concrete. Among other things, it was shown that the addition of steel fibers (contaminated with rubber) to approximately 1.3% reduces the shrinkage of concrete with these fibers by 7–10% compared to a fiber-free concrete matrix cured under the same conditions. Full article

Steel-cord conveyor belts are usually assessed using average damage indicators calculated for entire belt sections. Although such indicators are useful for general condition assessment, they do not adequately represent spatially non-uniform degradation across the belt width. This paper proposes a sensor-based, channel-wise framework for condition assessment, remaining useful life (RUL) estimation, and maintenance decision support for steel-cord conveyor belts. The approach uses data from consecutive non-destructive diagnostic scans, in which the belt cross-section is represented as a set of active measurement channels. For each channel, local damage density is treated as a health indicator evolving over time. A simple accelerating degradation model is then used to estimate local degradation intensity and channel-wise RUL. Three decision thresholds are introduced to represent entry into the refurbishment window, the end of economically justified refurbishment, and the critical removal condition. In addition to channel-wise RUL, the framework includes cross-sectional indicators such as the fraction of channels exceeding each threshold, the width of compact critical zones, and life-uniformity measures describing the spatial distribution of degradation. A cost-oriented interpretation is also introduced by linking non-uniform cross-sectional degradation with reduced life utilization and increased cost per unit operating time. The applicability of the framework is illustrated using consecutive diagnostic scans from an industrial conveyor belt loop. The results show that localized degradation may govern belt replacement earlier than average indicators suggest. The proposed approach provides a practical basis for condition-based maintenance, refurbishment planning, and future integration with loading-condition analysis and digital-twin-oriented diagnostics. Full article

Steel-cord conveyor belts are critical equipment in mining operations, and surface damage can easily lead to safety incidents. Therefore, achieving efficient and accurate damage detection is of significant importance. This study investigates a conveyor belt damage identification method based on the YOLOv7 object detection framework. First, a dedicated dataset of conveyor belt damage is constructed, annotated, and augmented using geometric and pixel-level transformations to support model training. To meet real-time detection requirements, the following two lightweight models are proposed on the basis of YOLOv7: GSConv-YOLOv7, which reconstructs the backbone network using GSConv to reduce parameter size and computational cost, and MobileViTv3-YOLOv7, which replaces the original backbone with MobileViTv3. Experimental results show that GSConv-YOLOv7 achieves an mAP of 84.6%, while reducing parameters and computation by 17.2% and 16.2%, respectively, and improving detection speed by 16FPSs. To further enhance accuracy, the MPDIoU loss function is adopted in place of CIoU, improving convergence and bounding box regression performance. Building upon this, an LSKNet attention mechanism is integrated, and most convolutional layers are replaced with RFAConv, resulting in the proposed YOLOv7-GPLF model. This model achieves an mAP of 88.1%, with parameter size and computational cost of 33.7 M and 94.5 G, respectively, and an inference speed of 54 FPSs. The model thus delivers significantly improved detection performance while remaining lightweight, enabling fast and accurate identification of conveyor belt damage. Full article

To improve detection accuracy for color-sensitive and small-target defects in steel cord ply, this paper introduces an improved YOLOv8s algorithm using multi-teacher stepwise hierarchical knowledge distillation for better adaptation across production lines. The improvements include: replacing the initial backbone convolutional layer with RGBV grouped convolution to enhance color feature extraction; substituting the SPPF module with SPPFCSPC-LSKA to improve multi-scale perception; and optimizing bounding box accuracy with the WIoU loss function. The multi-teacher distillation approach first transfers color feature learning using an RGBV-only teacher, then multi-scale feature learning with an SPPFCSPC-LSKA-only teacher. Experimental results show the improved model achieved 90.4% precision, 92.0% recall, 91.2% F1-score, and 97.2% mAP@0.5, surpassing the baseline YOLOv8s by 1.9, 2.2, 2.1, and 3.4 percentage points, respectively. The proposed model also achieves an inference time of 3.9 ms, representing a 1.0 ms reduction compared to the baseline. On a smaller dataset from another production line, single-teacher distillation increased precision, recall, F1-score, and mAP@0.5 to 84.6%, 82.0%, 83.3%, and 88.8%, respectively, albeit with an increase in inference time. The multi-teacher strategy further increased metrics to 97.5% precision, 88.8% recall, 92.9% F1-score, and 94.3% mAP@0.5, providing additional gains over single-teacher distillation while maintaining the same parameter count of 11.127 M and achieving a faster inference time of 4.1 ms on the target production line. Full article

This experimental study investigates the influence of selected bed joint reinforcement systems on the evolution of damage and crack development in masonry elements subjected to axial compression. Autoclaved aerated concrete masonry samples reinforced with steel truss reinforcement, unidirectional carbon fibre mesh and steel cords embedded in a fibreglass matrix were tested and compared to an unreinforced reference specimen. Full-field deformation and strain localisation were monitored using digital image correlation (DIC). The results indicate that bed joint reinforcement does not lead to a measurable increase in compressive load-bearing capacity, as differences in ultimate load remain within experimental uncertainty. However, clear differences in the evolution and spatial distribution of damage were observed. Steel truss reinforcement promoted strain redistribution and delayed localisation of tensile strains, while the remaining reinforcement systems exhibited only limited influence on crack morphology. The findings confirm that bed joint reinforcement in compressed masonry should be classified as a nonstructural solution and demonstrate the diagnostic value of full-field deformation monitoring for assessing damage evolution and crack control in masonry structures. Full article

Steel wire rods are essential for manufacturing high-strength steel tire cords. Yet, the presence of residual copper (Cu) in recycled steel can cause grain-boundary sensitization, embrittlement, and deterioration of the mechanical performance of the final product. This study introduces a desensitization heat treatment step designed to redistribute Cu away from austenite grain boundaries after sensitization occurs. The treatment consists of a 10 min dwell at 1000 °C in a 5%H₂-Ar reducing atmosphere followed by quench. The temperature and hold time were selected based on diffusion calculations to promote solid-state back diffusion of Cu without altering grain morphology. Experimental validation showed that the dwell step reduced the length of Cu-rich sensitized zones of steel wire rod samples containing 0.21 wt.% Cu by approximately 89% and restored the mechanical properties to nearly 95–98% relative to low-Cu baseline steel (0.01 wt.% Cu). Compared with sensitized and as-obtained samples, these results highlight the effectiveness of the proposed method in improving both the microstructure and tensile performance of recycled steel wire rods, enabling their potential application in tire manufacturing. Full article

This study analyses how the orientation of the measurement head in a magnetic diagnostic system affects the parameters of magnetic signals recorded during steel-cord conveyor belt inspection. The experiments were conducted on a laboratory test stand using a reference belt with artificial defects at two belt speeds and several sensitivity thresholds. Three types of head rotation were analyzed: longitudinal (OX), transverse (OY), and planar (OZ). For each configuration, a set of geometric signal parameters was calculated, including length, width, orientation, eccentricity, and solidity. The results showed that rotation about the OX axis caused the greatest geometric distortions (increased orientation_deg and eccentricity). Rotation about the OY axis produced amplitude asymmetry and changes in solidity (circularity), while rotation about the OZ axis resulted in twisting and displacement of the signal centroid. The total area (area_mm2) remained stable, confirming the geometric nature of the observed changes. Even small head deviations (5–10°) may introduce significant interpretation errors. Therefore, the application of geometric calibration and orientation compensation algorithms is recommended to improve the online diagnostic accuracy of the measurement system. Full article

In coal mine production processes, conveyor belts are essential components. They play a crucial role in minimizing the risk of belt failure, enabling unmanned operations in hazardous environments, digitally monitoring production metrics, and facilitating timely information feedback, all of which are vital. This paper provides a systematic review of the fundamental concepts, operational principles, and prevalent algorithms associated with conveyor belt detection technology. It summarizes recent research advancements and current applications in key areas while outlining future trends. The paper addresses the challenges of real-time detection during highspeed operations and the identification of defects in various internal filling materials. It evaluates the feasibility of employing methods such as X-ray detection, magnetic flux leakage detection, ultrasonic detection, radio frequency detection, and terahertz wave detection for high-speed conveyor belt inspection and defect identification in filling materials. Based on a comprehensive analysis, terahertz wave detection technology demonstrates significant potential for advancement in non-destructive testing of conveyor belts, owing to its broad applicability and ability to directly identify the location and size of damage. This review aims to provide technical support for selecting testing methods for steel cord conveyor belts. Full article

Steel reinforced grout (SRG) composites are widely used for strengthening existing structures. Galvanized (zinc-coated) ultra-high tensile strength steel cords are more durable than brass-coated and cheaper than stainless-steel ones, making them the most common in practice. While compliant with certification standards, corrosion may occur, potentially affecting tensile strength and bond capacity. The latter has, however, remained largely unexplored, highlighting a need to assess durability under different environmental exposures. This study investigated the durability of galvanized SRGs with four cord types and four mortar matrices (cement- and lime-based). Direct tensile, shear bond, and lap-tensile tests were conducted after immersion in saltwater or alkaline solutions, exposure to freeze–thaw or salt crystallization cycles, and high temperatures. Results highlighted salt exposure as the most critical condition, particularly with lime-based matrices. Zinc coating thickness proved essential for corrosion resistance, while freeze–thaw and salt crystallization led to bond degradation due to concentrated steel corrosion and mortar microcracking. The findings highlight the importance of considering appropriate protective measures and exposure-specific conditions when designing SRG reinforcements. Full article

This study presents the results of an investigation into the potential use of the DiagBelt+ magnetic diagnostic system for assessing the quality of conveyor belt splices. Splices in conveyor belts are susceptible to damage and irregularities resulting from assembly errors, improper vulcanization parameters, or unfavorable operational conditions. Detecting geometric deviations from the reference standard after splice fabrication can serve as a component of QA/QC systems. Later deviations may indicate material or fabrication defects. To date, applications of the DiagBelt+ system have been limited to locating damage within the belt and its splices. Recently, efforts have been made to extend the system’s functionality to include splice diagnostics. This study was conducted under laboratory conditions on an ST2500 belt featuring five splices (three bias and two straight splices). Data acquisition was performed under various configurations of measurement parameters, including sensor-to-belt distance, belt travel speed, and system sensitivity threshold. For each splice, the signal width was measured and analyzed as a potential indicator of splice geometry and quality. The results indicate that the DiagBelt+ system can be effectively used for splice diagnostics. Work has commenced on automating the splice quality assessment process. Full article

This article demonstrates that machine fires caused by a belt transmission are a fundamental and current research problem. The aim of this work is to identify the hazards during thermal decomposition and combustion of a transmission with a toothed belt, used as a drive or conveyor belt to synchronise mechanisms. The analysis distinguished belts in a polyurethane or rubber cushion with a Kevlar, steel, or polyurethane cord. The belts’ composite structure can be a source of unpredictable emissions and toxic substances of varying concentrations and compositions during thermal decomposition and combustion. To evaluate the compared belts, a testing methodology was used to determine the toxicometric indicators (W_LC50SM), according to which it was possible to assess the toxicity of the thermal decomposition and combustion products following EU standards. The analysis was carried out based on the recorded emissions of chemical compounds during the thermal decomposition and combustion of polymer materials at three different temperatures (450, 550, and 750 °C). The least favourable toxicometric indicators (W_LC50SM) are found in rubber cushion belts, which are very toxic (about 13 g/m³) and toxic (about 40 g/m³) materials. The results show that thermoplastic polyurethane cushion belts are moderately toxic materials, with a W_LC50SM index ranging from 411 g/m³ to 598 g/m³. Full article

Neck and lower back pain, often caused by spinal disorders such as scoliosis and degenerative disc disease, affects over 80% of the global population, with an estimated from 250,000 to 500,000 spinal cord injuries occurring annually according to the WHO. As the demand for spinal procedures continues to rise, advancements in implant materials have become essential. Orthopedic implants play a vital role in restoring mobility and improving the quality of life of patients with musculoskeletal disorders. Metallic implants, such as stainless steel, titanium, and its alloys, are commonly used to make fixation devices for spinal fusion surgery due to their excellent mechanical properties. However, complications such as stress shielding have been recorded. Polymeric materials offer new prospects as an alternative to metal-based materials such as those based on Polyaryletherketone (PEAK). Among the advanced materials used in these implants, PAEK has emerged as the preferred choice due to its exceptional mechanical strength, thermal stability, and chemical resistance. Polyetheretherketone (PEEK) and Polyetherketoneketone (PEKK) offer notable advantages, such as radiolucency and mechanical properties resembling those of natural bone, reducing stress shielding and facilitating postoperative imaging. Although PEEK and PEKK are considered as bioinert, it has been demonstrated that adding bioactive agents such as hydroxyapatite (HA) into the matrix to make composites solves this problem and can help with aiding direct bone apposition. Furthermore, PAEK’s compatibility with 3DP enables the creation of patient-specific implants with intricate geometries, enhancing the surgical outcomes. In addition, the lattice structures of orthopedic implants can alleviate stress shielding, provide an enhanced surface area for the release of bioactive agents (or antimicrobial materials), and eliminate more imaging artifacts compared to that of simple, solid metal implants. PAEK/HA composite implants represent a transformative solution, addressing the psychological, social, and economic burdens of spinal disorders, while enhancing the surgical outcomes. With continuous technological evolution, PAEK/HA composites are poised to play a pivotal role in modern spinal care. Full article

Autologous-engineered artificial tissues constitute an ideal alternative for radical surgery in terms of natural anticoagulation, self-repair, tissue regeneration, and the possibility of growth. Previously, we focused on the development and practical application of artificial tissues using “in-body tissue architecture (iBTA)”, a technique that uses living bodies as bioreactors. This study aimed to further develop iBTA by fabricating tissues with diverse shapes and evaluating their physical properties. Although the breaking strength increased with tissue thickness, the nominal breaking stress increased with thinner tissues. By carving narrow grooves on the outer periphery of an inner core with narrow grooves, we fabricated approximately 2.2 m long cord-shaped tissues and net-shaped tissues with various designs. By assembling the two inner cores inside the branched stainless-steel pipes, a large graft with branching was successfully fabricated, and its aortic arch replacement was conducted in a donor goat without causing damage. In conclusion, by applying iBTA technology, we have made it possible, for the first time, to create tissues of various shapes and designs that are difficult using existing tissue-engineering techniques. Thicker iBTA-induced tissues exhibited higher rupture strength; however, rupture stress was inversely proportional to thickness. These findings broaden the range of iBTA-induced tissue applications. Full article

Dredging hoses are flexible and are particularly suitable for slurry transportations for mud or sand in dredging projects. To achieve sufficient bending stiffness and to prevent the pipe body from collapsing, this type of hose segment is a composite structure that is embedded with several cord reinforcement layers and steel wires in its rubber layer. To quickly evaluate the nonlinear bending mechanical properties of rubber hoses, this study proposes the equivalent stiffness method of linear superposition, which is verified by test data and numerical results. The results show that the equivalent bending stiffness method proposed in this study is in good agreement with numerical and experimental results. Then, by comparing the calculation results of the hose string, it was demonstrated that the linear stiffness superposition method proposed in this study can also accurately predict the bending mechanical behavior characteristics of string hose, and provide reliable guidance for hose design in practice. Full article

Because of their superior performance, flexible strain sensors are used in a wide range of applications, including medicine and health, human–computer interaction, and precision manufacturing. Flexible strain sensors outperform conventional silicon-based sensors in high-strain environments. However, most current studies report complex flexible sensor preparation processes, and research focuses on enhancing and improving one parameter or property of the sensors, ignoring the feasibility of flexible strain sensors for applications in various fields. Since the mechanical properties of flexible sensors can be well combined with rubber conveyor belts, in this work polydimethylsiloxane (PDMS) was used as a flexible substrate by a simple way of multiple drop coating. Graphene-based flexible strain sensor films that can be used for strain detection at the joints of steel cord core conveyor belts were successfully fabricated. The results of the tests show that the sensor has a high sensitivity and can achieve a fast response (response time: 43 ms). Furthermore, the sensor can still capture the conveyor belt strain after withstanding high pressure (1.2–1.4 MPa) and high temperature (150 °C) during the belt vulcanization process. This validates the feasibility of using flexible strain sensors in steel wire core conveyor belts and has some potential for detecting abnormal strains in steel wire core conveyor belt, broadening the application field of flexible sensors. Full article