bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Lightweight Model of Automatic Pixel-Level Detection for Weld Defects
Authors: Qian Weichao , Dong Shaohua , Ren Qingying , Chen Lin 
Published: November 2024

Abstract
Pipeline transportation serves as the primary method for conveying oil and gas, with welding being the predominant means of connecting pipelines. Nevertheless, weld defects frequently occur at circumferential welds due to various factors including the welding process and environmental conditions. Failures due to these welding defects threaten the safety of pipeline transportation, and X-ray inspection is used to visually detect defects. While manual inspection has traditionally been employed for X-ray defect detection, it suffers from inefficiency and subjectivity. As computer vision techniques have advanced, methods leveraging deep learning have emerged for weld defect detection. However, the practical application of deep learning methods is constrained by their size, limiting their effectiveness in industrial detection tasks. To address these challenges, this paper proposed a lightweight pixel-level automatic detection network for weld defects based on an encoder-decoder structure. Firstly, a lightweight global feature extraction block utilizing self-attention was introduced to enhance detection performance by extracting more discriminative features within defect areas. Subsequently, a high-low level feature fusion block was incorporated to mitigate feature loss resulting from downsampling. Additionally, the depthwise separable convolution was employed to further reduce network size. Our method demonstrated superior detection performance compared to other advanced methods, as evidenced by qualitative comparison and quantitative analysis, with dice coefficient (DICE) and intersection over union (IoU) scores of 0.881 and 0.789, respectively. Moreover, our network exhibited significantly reduced size compared to other advanced detection methods. Thus, the proposed detection network holds considerable promise for effectively detecting weld defects.
Strain-Rate-Dependent Parameters of Lithium as a Plasma Facing Material for Magnetized Target Fusion Application
Authors: Miao Yu , Sexsmith Michael , Hartono Soegi , Preston Claire , Tsai Benjamin , Dick Jean-Sebastien , Sirmas Nick 
Published: November 2024

Abstract
Lithium is an ideal plasma facing material for fusion plasmas due to its low atomic mass, ability to breed tritium fuel and its gettering characteristics. Liners made of lithium are used as magnetic flux conservers, which can be compressed for Magnetized Target Fusion (MTF) applications. Lithium has been extensively examined in the literature aiming at its mechanical properties for its various applications, and yet the knowledge about its mechanical properties is insufficient for the MTF application in two aspects. First, most of the available studies focus on the quasi-static loading cases. Second, the tests in those studies were commonly performed via uniaxial tensile test where the stress state was not representative for the compression loading scenario.
In this paper, we present an approach to estimate parameters that govern lithium’s behavior at high strain rates up to 500 s−1. In our approach, a series of drop-piston experiments were combined with ANSYS LS-DYNA simulation to determine the material parameters. The bi-linear strain hardening model and Johnson-Cook material model were considered in our studies where the former one accounts for the plastic stress-strain relationship and the latter one describes the plastic stress-strain relationship with the strain-rate effects. In our drop-piston experiments, we use high-speed camera imaging and a feature tracking algorithm to record the velocity and extract the piston impact time. A bi-linear strain hardening model was initially used to estimate plastic behavior of lithium. The strain-rate dependent material parameters were then determined using a reverse engineering approach with the help of numerical simulations that reproduce the tests. A series of numerical simulations with different combinations of material parameters were computed to establish the combination of material parameters that best fit the test results.
The proposed material model will be used in the lithium compression experiments for MTF applications, which accounts for the hardening behavior at different strain rates.
Benchmark Analysis on Pipe Support Structures for Establishing Inelastic Seismic Design
Authors: Nakamura Izumi , Takito Kiyotaka , Shimazu Ryuya , Okuda Yukihiko , Sakai Michiya , Otani Akihito , Watakabe Tomoyoshi , Okuda Takahiro , Shibutani Tadahiro , Shiratori Masaki 
Published: November 2024

Abstract
A new seismic design procedure which evaluates the inelastic behavior of piping system by detailed finite element method (FEM) analysis has been developed in Japan (the JSME CC); however, the inelastic behavior is only considered for pipe body in the JSME CC, and the evaluation of inelastic behavior of pipe support structure is still not included.
To clarify the current analytical accuracy of inelastic analysis of pipe support structures and to develop an analytical guideline to reasonably include the inelastic behavior of pipe support structure in the seismic design of piping system, a series of benchmark analysis on pipe support structures has been launched in 2022. The benchmark analysis of pipe support structures consists of mainly two stages; the first stage is the analysis of pipe support structures themselves, and the second stage is the analysis of piping system with inelastic pipe support structure.
As of January 2024, the first stage of benchmark analysis is in progress. It is confirmed that there are some variabilities in modeling of support structures, stress-strain relationship, and boundary conditions. The load-deflection relationships also show variability even when the support structures are in the elastic region. The effect of these variations to the response of piping system model is remained as future tasks.
Environmental Effect on Fatigue Life of Stainless Steel for Superimposed Waveforms Simulating High-Cycle Thermal Fatigue
Authors: Kamaya Masayuki 
Published: November 2024

Abstract
The degree of fatigue life reduction due to a pressurized water reactor (PWR) environment depends on strain rate. The environmental effect is negligibly small when the strain rate is sufficiently large. In general, the environmental effect is not considered in fatigue life assessments of high-cycle thermal fatigue, which has been observed at mixing tees of nuclear power plant piping systems. Although frequency of strain fluctuation caused by thermal striping is relatively high, it was found that the main source of fatigue damage was a relatively low-frequency strain fluctuation superimposed on the high-frequency strain fluctuation. In this study, to investigate the environmental effect on the high-cycle thermal fatigue, fatigue tests were conducted for superimposed waveforms in which high-frequency strain superimposed on the low-frequency strain fluctuation. Five loading patterns were tested in the PWR water environment using Type 316 stainless steel specimens. Also, tests in air were conducted for the same loading patterns. It was revealed that the degree of the environmental effect of the superimposed waveforms depended on the strain rate of high-frequency strain fluctuation rather than that of low-frequency strain fluctuation. It was concluded that, even though the high-cycle thermal fatigue failure was brought about by the low-frequency strain fluctuation, the environmental effect did not necessarily have to be considered in the fatigue assessment.
Vortex Shedding Characteristics of Concentric Circular Rod Bundle Arrangements
Authors: Huang Zhengfeng , Wang Heng , Lv Hong , Zhu Guorui 
Published: November 2024

Abstract
The concentric circular arrangement of bundles is widely used in the nuclear industry. The study of the vortex shedding characteristics of concentric circular arranged bundles can provide a reference for the design, manufacturing and maintenance of this type of heat exchanger. This research aims to thoroughly investigate the vortex shedding characteristics of concentric circular arranged bundles under different arrangement patterns (approximately triangular arrangements, approximately square arrangements, and transitional arrangements) and different Pitch-to-diameter ratios (1.25, 1.5, 1.75, and 2.0). Through numerical simulation, the lift coefficient was monitored to obtain data on vortex shedding, and the vortex shedding frequency was obtained using Fourier transformation. The study reveals that the most significant vortex shedding phenomenon occurs in the approximately square arrangement, followed by the approximately triangular arrangement, and finally the transitional arrangement. The approximately triangular arrangement exhibits flow characteristics similar to those of the equilateral triangle arrangement, and the difference in lift coefficient does not exceed 3%. Pitch Ratio is identified as a major factor influencing vortex shedding. The increase in Pitch Ratio significantly enhanced the vortex shedding. Moreover, the vortex shedding in the bundles is greatly influenced by neighboring tubes, resulting in a diminished manifestation of vortex shedding. The research results provide certain reference significance for the engineering practice of selecting arrangement methods and pitch-to-diameter ratios in concentric circular tube bundle heat exchangers.
The Safety Assessment of Tanker Truck due to Collision in Rollover Accidents
Authors: Feng Heyi , Xu Xiaodong , Deng Guide , Kang Xiaopeng , Li Yongquan , Jia Guodong 
Published: November 2024

Abstract
Tanker truck is an important way to carry fuel and hazardous materials in land transportation. In recent years, many tanker truck rollover accidents occurred, some of them are severe, causing casualties and significant economic losses. Therefore, it has come to public’s attention that how to avoid such accidents. This study performs the safety assessment of tanker truck due to collision in rollover accidents. The critical speed of the truck is determined using a multibody dynamic analysis software, ADAMS CAR. Then the collision analysis that study the structural response of tanker hitting on ground, curbstone, and concrete blocks are performed using ANSYS/LS-DYNA. The material parameters are obtained through experiments using specimens manufactured by a cut-off plate from a tanker involved in a rollover accident. The overturn analysis results show that the critical speed of the tanker truck is 39.46 km/h. The results of tanker hitting on the ground show that this process would cause significant deformation at connection joints of heads and tanker body, but it does not cause tanker failure. On the other hand, the tanker body is more likely to fail when concrete block that happens to hit on tanker next to baffles.
Prediction of Burst Pressure for Type IV High-Pressure Hydrogen Storage Vessel Based on Adaptive Meshing Method
Authors: Li Fanding , Chen Xuedong , Fan Zhichao , Xu Peng , Tao Jiahui , Wang Zhe 
Published: November 2024

Abstract
With the growth of the hydrogen energy industry, cost-effective and highly reliable high-pressure hydrogen storage technologies have gained increasing attention. High-pressure hydrogen storage vessels with plastic inner liners and composite materials (Type IV hydrogen vessels) have inherent advantages such as high hydrogen storage density, corrosion resistance, and excellent fatigue performance, making them one of the most advanced high-pressure hydrogen storage methods. Burst pressure is a critical performance indicator for Type IV hydrogen storage vessels. Due to the complex structure of Type IV high-pressure hydrogen storage vessels, material property variations in different parts, multiple failure modes for composite materials, and substantial influencing factors, experimental testing for structural design and performance optimization is challenging, time-consuming, and expensive. The numerical simulation method is an adequate way to reduce development costs. With the progressive damage method, burst pressure can be precisely predicted. However, the finite element model has an excessively high degree of freedom, resulting in low computational efficiency.
In response to the need for precise and efficient performance simulation of Type IV high-pressure hydrogen vessels, this paper proposed a framework to effectively reduce the resources needed for finite element calculations on multiple layup schemes based on an adaptive meshing method. Finite element models that include the fiber orientations and geometric details on dome parts and cylinder part are established. Various damage modes are considered and coupled with the progressive damage method. Comparative analysis of different meshing methods has been carried out to study the influence of meshing parameters on the calculation speed. With data processing and programmable finite element software, a burst pressure prediction method for Type IV hydrogen storage vessels based on adaptive meshing is proposed. Burst tests have been further taken, which indicate that the numerical results match the experiment well. Meanwhile, the adaptive meshing method significantly improves calculation speed and with satisfying accuracy. In conclusion, the framework proposed in this paper offers valuable insights into data collection speed for Type IV hydrogen storage vessels with complex layup schemes and advances the utilization of numerical simulation in the domain of hydrogen energy storage and transportation equipment.
The Development of Hydrogen Energy Equipment Safety Certification in China
Authors: Li Jun , Li Jiepu , Guan Chenxi , Zhang Songsong , Li Xiang , Liu Xu 
Published: November 2024

Abstract
In recent years, the hydrogen energy industry in China has experienced rapid development, leading to intensified research and development efforts in hydrogen energy equipment. As the cornerstone of the entire hydrogen energy industry chain, hydrogen energy equipment has experienced significant advancements. However, hydrogen energy equipment certification is still in its preliminary exploration stage, and the corresponding certification system lacks maturity, hindering the subsequent industrialization and reliability of hydrogen energy equipment in China. This article initiates with an introduction to the concepts of product certification and safety certification, elucidating the model and necessity of safety certification for hydrogen energy equipment. It subsequently provides a brief overview of the current state of safety certification for hydrogen energy equipment, touching on standards, technical specifications, inspection, testing capabilities, and other relevant aspects. Several issues are identified within the safety certification of hydrogen energy equipment in China: (1) The foundational theories pertaining to hydrogen energy equipment are inadequate, leading to the incompleteness of relevant product standards and technical specifications; (2) Scarcity of safety certification type test devices and a deficiency in certification institutions possessing international certification capabilities. (3) Limited safety certification projects for hydrogen energy equipment in China. In light of these challenges, targeted suggestions are proposed for the future development of hydrogen energy equipment safety certification in China. These recommendations aim to guide the standardization and systematization of hydrogen energy equipment, ensuring its high-quality development and secure operation. The ultimate goal is to establish a robust safety certification system for hydrogen energy equipment in China.
Preparation and Properties of the Low-Cost Heat-Resistant Rubber Material for Trenchless Rehabilitation of Thermal Pipelines
Authors: Wang Zhongzhen , Li Yao , Yasin Sohail , Zheng Ce , Hu Peiyu , Zhang Liang , Shi Jianfeng 
Published: November 2024

Abstract
Trenchless rehabilitation technology is a pipeline repair technology with the advantages of high construction efficiency and low impact on the environment. It is currently used in the repair of drainage pipelines and oil pipelines. Thermal pipelines transport hot water or hot steam from heat sources to buildings. They are an essential part of urban heating systems. With the increase in elapsed service life, thermal pipeline failure occurs frequently, so it is necessary to apply trenchless rehabilitation technology to repair thermal pipelines to improve the speed and efficiency of repair. However, the temperature of the conveying medium in thermal pipelines can reach 100°C, and plastic materials such as polyethylene (PE), commonly used in trenchless repair technology, cannot withstand the high working temperature. There are heat-resistant rubber materials with excellent properties, but the prices are too high to be widely used in trenchless rehabilitation technology. Therefore, this study analyzed the material temperature resistance and mechanical property requirements for applying trenchless rehabilitation technology to thermal pipelines. Using natural rubber (NR) and ethylene propylene diene monomer (EPDM) rubber as the matrix, the low-cost heat-resistant rubber material was successfully prepared by adding deep eutectic solvents (DES). The mechanical properties and heat aging resistance of the rubber material were tested. The results show that the rubber material has excellent mechanical properties and can meet the usage conditions of thermal pipelines. After aging at 150°C for 200 hours, the mechanical properties of the rubber material can still be maintained at a high level, meeting the long-term requirements of thermal pipelines. After economic analysis, the price of this rubber material was lower than 10 dollars per kilogram and can be applied in trenchless rehabilitation technology.
Analysis of the Tribological Behaviour of Titanium Fasteners Under Different Tightening Strategies
Authors: De Agostinis Massimiliano , Croccolo Dario , Fini Stefano , Mele Mattia , Olmi Giorgio , Scapecchi Chiara , Martini Jacopo 
Published: November 2024

Abstract
The present work aims at investigating the tribological behaviour of Ti6Al4V, M6 screws, applied to cast aluminium underhead and threads, when subjected to different tightening strategies. All tightenings have been performed in the dry condition, after degreasing of the cast parts by means of a commercial spray degreaser. Namely, a standard steady tightening operation at 20 rpm has been compared to a mixed high speed – standard speed strategy (200 rpm – 20 rpm), observing the tribological output in terms of underhead and thread friction coefficients at first tightening. All measurements have been performed by means of a tightening test bench that allows sampling the separate frictional contributions at the underhead and at the thread. For each specimen, force – torque diagrams have been plotted and observation of the underhead surfaces have been performed (before and after first tightening). The underhead and thread friction coefficients have been sampled at both 25% and 100% of the target tightening torque. The main outcomes of the study are: (i) the frictional behaviour of the Ti6Al4V screw, mating to aluminium substrates is nearly the same for both tightening strategies, in terms of average total coefficient of friction; (ii) in the case of mixed high – low speed strategy, a slightly better behaviour in terms of stick slip occurrence has been observed at first tightening, (iii) both processes allow achieving friction coefficients in the range suggested by the relevant standards.
Ultrasonic Phased Array Automatic Detection on Weld Seams of Plastic Liner in Type IV Hydrogen Cylinder
Authors: Miao Cunjian , Zhong Haijian , Teng Guoyang , Guo Weican , Tang Ping , Hu Jiansheng , Tao Yangji 
Published: November 2024

Abstract
On-board 70MPa Type IV hydrogen cylinders predominantly employ an injection-molded plastic liner with a welded design. During the welding sequence, parameters such as temperature, pressure, and duration, coupled with the quality of raw materials, can potentially instigate welding inconsistencies. These aberrations can subsequently compromise the impermeability of the plastic liner. Due to the plastic liner’s relatively thin thickness, the significant acoustic attenuation of the material, and the complex nature of defect formations, conventional ultrasonic inspection methods struggle to effectively detect defects within these liners.
An ultrasonic phased array automatic detection technique, tailored for the weld seams of Type IV hydrogen cylinder plastic liners, was introduced. By harnessing the capabilities of water wedge technology, it facilitates the deflection of ultrasonic beams and the transition of waveforms. Employing curved elements for intrinsic self-focusing and array elements for electronic focusing, this technique achieves bidirectional acoustic emission fields. Building upon the foundational insights from this acoustic field simulation, the phased array focusing principle, sensor orientation, array element number, pitch, and operational frequency, among other pivotal inspection determinants, were meticulously optimized and calibrated. A phased array multi-path imaging detection method for the liner’s weld seam was formulated, and an analysis was undertaken to evaluate the detection efficacy and sensitivity across various defect types.
Building on the aforementioned research foundation, a specialized ultrasonic phased array immersion C-scan automatic detection system, specifically designed for the weld seams of the plastic liner, was developed. Test sample of the plastic liner weld seam, integrated with artificial defects, were subjected to testing. The results demonstrated that this method could reliably detect artificial defects in the test sample. This methodology was also successfully implemented in the welding production line for inspection of actual plastic liner products, ensuring the integrity of the welding quality.