A NEURAL NETWORK FOR WELD PENETRATION CONTROL IN GAS TUNGSTEN ARC WELDING

Realizing of weld penetration control in gas tungsten arc welding requires establishment of a model describing the relationship between the front-side geometrical parameters of weld pool and the back-side weld width with sufficient accuracy. A neural network model is developed to attain this aim. Welding experiments are conducted to obtain the training data set （including 973 groups of geometrical parameters of the weld pool and back-side weld width） and the verifying data set （108 groups）. Two data sets are used for training and verifying the neural network, respectively. The testing results show that the model has sufficient accuracy and can meet the requirements of weld penetration control.

Modern Health Worries and the Personality Disorders: Two Studies Using Different Measures

This paper reports on two studies using different measures of both Modern Health Worries (MHW) and the Personality Disorders (PDs) to establish the relationship between the two concepts. Study 1 used the PID-5 which is a measure of maladaptive personality traits and the extended 40 item MHW scale. Study 2 used the original 28 item measure of MHW and PDs as measured by the Coolidge Axis-II Inventory—Short Form: SCATI. In study 1 a regression on the total MHW scale accounted for 14% of the variance: those who scored higher on Antagonism and Negative Affect had higher MHW scores. In the study 2 regressions showed four variables consistently related to MHW: sex (females with higher scores), optimism, political beliefs (left wing liberals with higher scores) and those with Cluster B personality disorders (dramatic, overly emotional, erratic). There was enough overlap in the two studies to conclude that various PDs mainly from Cluster B (Moving Against others) were modestly related to MHW as predicted. Limitations and implications are considered.

Numerical simulation of dynamic thermal process during doublesided asymmetrical TIG backing welding of large thick plates

The dynamic thermal process during double-sided asymmetrical TIG backing welding of large thick plates （ 1 000 mm×700 mm×50 mm） is numerically simulated using MSC. MARC. The effect of arc distance on the thermal cycle in weld zone during double-sided asymmetrical T1G backing welding is investigated. The results show that the workpiece experiences double-peak thermal cycle in double-sided asymmetrical TIG backing welding. On the one hand, the fore arc has the pre- heating effect on the rear pass, and the pre-heating temperature depends on the distance between the double arcs, the heat input of fore arc, and the initial temperature of workpiece. On the other hand, the rear arc has the post-heating effect on the fore pass. The mutual effects of two heat sources decrease with the increase of arc distance.

Double-sided gas tungsten arc welding process on TC4 titanium alloy

TC4 titanium alloy was welded by double-sided gas tungsten arc welding(GTAW) process in comparison with conventional GTAW process, the microstructure and mechanical performance of weld were also studied. The results indicate that double-sided GTAW is superior over regular single-sided GTAW on the aspects of increasing penetration, reducing welding deformation and improving welding efficiency. Good weld joint was obtained, which can reach 96.14% tensile strength and 70.85% elongation percentage of the base metal. The grains in heat-affected zone(HAZ) are thin and equiaxed and the degree of grain coarsening increases as one moves to the weld center line, and the interior of grains are α and α′ structures. The coarse columned and equiaxed grains, which interlace martensitic structures α′ and acicular α structures, are observed in weld zone. The fracture mode is ductile fracture.

Study on welding deformation of the side beam based on numerical simulation method

The welding deformation is a key factor affecting the production quality of the side beam of the subway bogie frame. A major issue is how to control the welding deformation during the manufacturing processes. Based on the ＂Local- Global＂ method, the thermal cycle and the stress of a local model extracted from the global side beam model were simulated. The simulated strain result was mapped into the global model as an initial load to simulate the welding assembly deformation. Then the deformation distribution of the side beam was obtained by elastic finite element method, and compared with the measurement results. Furthermore, the welding deformation under different welding sequences and constraints was simulated. The influence of the welding sequences and constraints on the side beam deformation was analyzed. The results indicate that the deformation is the smallest when the sequence is symmetrical and decreases with the increase in constraints.

Numerical Simulation of Current Density Distribution in Keyhole Double-Sided Arc Welding

In the double-sided arc welding system (DSAW) composing of PAW+TIG arcs, the PAW arc is guided by the TIG arc so that the current mostly flows through the direction of the workpiece thickness and the penetration is greatly improved. To analyze the current density distribution in DSAW is beneficial to understanding of this process. Considering all kinds of dynamic factors acting on the weldpool, this paper discusses firstly the surface deformation of the weldpool and the keyhole formation in PAW+TIG DSAW process on the basis of the magnetohydrodynamic theory and variation principles. Hence, a model of the current density distribution is developed. Through numerical simulation, the current density distribution in PAW+TIG DSAW process is quantitatively analyzed. It shows that the minimal radius of keyhole formed in PAW+TIG DSAW process is 0.5 mm and 89.5 percent of current flows through the keyhole.

Personalized targeted therapy for esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma continues to heavily burden clinicians worldwide. Researchers have discovered the genomic landscape of esophageal squamous cell carcinoma, which holds promise for an era of personalized oncology care. One of the most pressing problems facing this issue is to improve the understanding of the newly available genomic data, and identify the driver-gene mutations, pathways, and networks. The emergence of a legion of novel targeted agents has generated much hope and hype regarding more potent treatment regimens, but the accuracy of drug selection is still arguable. Other problems, such as cancer heterogeneity, drug resistance, exceptional responders, and side effects, have to be surmounted. Evolving topics in personalized oncology, such as interpretation of genomics data, issues in targeted therapy, research approaches for targeted therapy, and future perspectives, will be discussed in this editorial.

Study on heat efficiency of laser-TIG double-side welding

A series of laser-TIG double-side welding experiments for aluminum alloys were carried out to investigate the heat efficiency of the process. The melting efficiency was introduced to evaluate quantitatively the degree of the mutual effect of the laser and the arc. The results showed that the melting efficiency of laser-TIG double-side welding exceeded the sum of the laser and the arc taken separately. With the increase of heat input, the weld depth and melting efficiency of the laser and the arc were increased signifwantly. This, in fact, implies the strong mutual effect of the laser and the arc as heat sources joined simultaneously in the process. Comparatively, the higher efficiency of the laser constituent of heat sources plays the main role in the increase of the process efficiency. The phenomena of arc column convergence, increased laser absorptivity and the formation of heat accumulation region are the causes of the improvement of heat efficiency.

Analysis of Vibration Frequencies of Piezoelectric Ceramic Rings as Ultrasonic Transducers in Welding of Facial Mask Production

The explosive demands for facial masks as vital personal protection equipment(PPE)in the wake of Covid-19 have challenged many industries and enterprises in technology and capacity,and the piezoelectric ceramic(PZT)transducers for the production of facial masks in the welding process are in heavy demand.In the earlier days of the epidemic,the supply of ceramic transducers cannot meet its increasing demands,and efforts in materials,development,and production are mobilized to provide the transducers to mask producers for quick production.The simplest solution is presented with the employment of Rayleigh-Ritz method for the vibration analysis,then different materials can be selected to achieve the required frequency and energy standards.The fully tailored method and results can be utilized by the engineers for quick development of the PZT transducers to perform precise function in welding.

Effect of arc distance on temperature field and weld shape during double-sided arc welding

A new high efficiency welding method, double-sided double arc welding with double powers （DSAW-D）, is developed for thick plate of low alloy high strength steel in this study. It is well known that the thermal cycles have an important influence on the microstructure, shape, stress, distortion and mechanical property. The DSA W-D method can control the temperature field on a wide range by regulating the distance between two arcs, improve the microstructure and prevent hot and cold cracking of high strength steel. But at present, the effect of arc distance on the temperature field and shape is not clear. Therefore, the paper researches the effect of arc distance on the temperature field and weld pool during DSAW-D using finite element method. The transient temperature field of different arc distance in DSAW-D is calculated. To verify the numerical results, the temperature is measured by the thermo-couple and the calculated results agree approximately with experimental data. Farther, the thermal property and mutual effect of double-sided arcs are investigated. The temperature distributions and weld pool profile at different arc distances are obtained. The results show that arc distance is a very important factor to affect the heat process.

Effect of laser parameters on arc behavior of laser-TIG double-side welding for aluminum alloy

The influence of laser parameters on are beharior of laser-TIC, dauble-side welding was investigated by utilizing CCD sensor and intage processing methods. It was found that are images had an obvious transformation from laser preheating to laser plasma ejected from the keyhole bottom, resulting in the phenomena of arc column convergence and arc root constrictian. The attraction phenomenon of the laser and the arc is also found in laser-TIG double-side welding. More noteworthy is that the behavior of arc attraction or constriction became much obvious at a lower current or laser plasma ejected from the keyhole bottom. The decrease in arc voltage had a certain relation u＇ith the improvement of arc stabilio.

欧盟GDPR五年执法反思:成效、挑战与经验

欧盟《通用数据保护条例》(GDPR)的率先实施对世界各国个人数据隐私保护立法与执法有着重要而深远的影响。本文基于数据隐私事务网站Privacy Affairs 2018—2023年发布的1 701起GDPR违规处罚案件,构建GDPR执法成效评价框架,量化其规制目标与规制结果。研究发现,GDPR过去五年执法实践中存在三大双面效应:数据侵权严监管与合规操作弱指引并存,保护个人数据隐私与促进数据产品创新两难,技术影响复杂与立法前瞻不足交织。鉴于此,中国的数据立法亟待加强新兴技术基于风险的前瞻规制,数据执法宜完善司法诠释与合规指引。

协同双面搅拌摩擦焊接技术

协同双面搅拌摩擦焊接(SDS-FSW)作为搅拌摩擦焊接技术的一种新的改进形式,显著改善了传统搅拌摩擦焊接变形大、焊接效率低等问题,对焊接质量也有提升作用,适用于大尺寸、大厚度的板材或型材的焊接。但目前SDS-FSW仍处于初始研发阶段,相关的理论及应用研究较少,研究成果主要集中在6061铝合金上。本文主要介绍SDS-FSW技术的发展历程、技术特点与典型研究结果及应用前景,以期为SDS-FSW技术的发展及实际工程推广提供参考。

张思德精神融入新时代青年理想人格培育研究

张思德精神的核心是全心全意为人民服务,其主要内容是人民至上、不怕牺牲、任劳任怨、奋勇当先。张思德精神是中国共产党的宝贵精神财富,是中国共产党人精神谱系的重要组成部分。张思德精神激励中国共产党人战胜日本帝国主义,解放亿万中国人民,彻底结束了中国饱受侵略的屈辱历史。张思德精神是新时代青年正心明志的坐标、立德修身的主调、敢于担当的根基。当下,教育主体需要弘扬张思德精神,通过深化理论教育、夯实思想基础,加强榜样引领、激发精神力量,优化育人环境、形成良好氛围等路径,培育青年理想人格。

缆式焊丝GMAW焊缝截面侧偏行为机理分析

缆式焊丝熔化极气体保护电弧焊(gas metal arc welding,GMAW)中存在的焊缝截面侧偏现象会导致焊接接头熔合不良,基于熔滴受力分析和最小电压理论对焊缝截面侧偏现象的变化规律进行机理分析.结果表明,电流是影响截面侧偏的关键因素,由于缆式焊丝独特的绞合结构引起电弧旋转,进而导致出现熔滴受力不均的现象,熔滴过渡方向与焊丝轴线存在夹角,在熔滴冲击力的作用下导致焊缝截面出现侧偏现象,随着电流的增加,电弧对熔滴的拘束增强,熔滴过渡方向逐渐趋于轴线,因而焊缝截面侧偏的趋势随着电流增加而减小.

厚板5A06铝合金万瓦级扫描激光立焊组织与性能

针对厚板铝合金万瓦级常规激光焊接往往存在焊缝成形差和气孔缺陷严重的问题,文中提出了厚板铝合金万瓦级扫描激光立焊方法,采用厚板5A06铝合金进行了焊接工艺试验,并综合分析了焊接接头焊缝成形、微观组织、力学性能.结果表明,该方法有效的改善了厚板铝合金常规激光的焊缝成形,且减少了气孔缺陷.根据熔池形貌图像,扫描激光大幅增加了熔池尺寸,因此熔池尾部受熔池前沿激光干扰减弱,有利于改善熔池尾部焊缝成形和减少气孔缺陷.针对厚度为50 mm铝合金板,采用万瓦级扫描激光立焊实现了窄间隙坡口形式24 mm厚钝边的双面双道焊接.当扫描幅度增大时,即焊接参数Ⅱ和Ⅲ,焊缝均匀光滑,成形良好,且X射线探伤未见气孔缺陷.焊接参数Ⅱ接头微观组织全部由等轴晶构成,焊接参数Ⅲ接头由等轴晶和少量柱状晶构成.由于焊接参数Ⅲ焊接速度小,热输入更大,焊接参数Ⅲ接头晶粒尺寸更大.焊接参数Ⅱ和Ⅲ接头抗拉强度为337 MPa和322 MPa,分别达到了母材的93.6%和89.4%,焊缝性能良好.焊缝拉伸断口均呈现韧窝形态,为韧性断裂.

压力管道工程中有关焊接诸多认知误区和盲区浅析(一)——焊接接头

焊接接头形式和焊缝形式是两个不同概念,而压力管道单面焊焊接接头要达到相当于双面焊同样质量要求是一个综合性的问题,主要涉及焊接方法、母材类别、焊接材料、焊接位置、预热、背面充气保护、热处理、电特性及技术措施等9个因素的影响,同时也与焊工技能有关。熟练焊工按照合格的焊接工艺评定进行施焊、加强焊缝目视检测(VT),尤其是焊接接头坡口加工和焊道VT检测是保障质量的重要要素。

基于Plant Simulation的白车身侧围焊装线仿真与优化

虚拟仿真技术是目前对焊装生产线进行工艺规划的主要手段。在分析某汽车白车身侧围焊装线的基础上,利用仿真软件Plant Simulation对侧围焊装线建立离散系统仿真模型,对设备工作情况和瓶颈工位进行分析,评估焊装线生产能力;通过设计Experiment Manager分析模块中的多因子试验,将焊装线产量作为指标,暂存区容量及添加位置作为影响因子,对暂存区的配置进行研究。结果表明合适的暂存区容量和添加位置能极大提高焊装线生产能力,为焊装线的优化提供理论依据和科学参考。

基于旁轴视觉的激光焊接系统加工定位方法

针对激光焊相机标定精度低,定位精度与像素当量倍数相差较大等问题,提出了一种基于旁轴视觉的相机标定方法和定位方法,通过内参标定校正透镜畸变;通过外参标定,建立系统中像素坐标系与机床坐标系间的转换关系,设计一种二值化阈值的局部寻优算法,以保证工件准确的边缘拟合.通过识别工件角点和一边的角度,确定工件在系统中的摆放位置与姿态,算法精度稳定在1像素内,即0.017 mm的理论精度,通过加工试验测试定位精度,在试验中对识别的工件转角角度进行修正,修正前,x方向平均误差0.050 mm,y方向平均误差0.137 mm;修正后,x方向平均误差为0.029 mm,y方向平均误差为0.026 mm,分别为像素当量的2.12倍和1.53倍,实际误差与像素当量间倍数相差较小.结果表明,该定位方法在充分利用相机性能的同时,具有较高的算法精度和定位精度,提高加工效率满足实际生产需求.

铝合金的电阻对接点焊模拟仿真与组织研究

利用Abaqus软件建立了厚度为4 mm的5052铝合金电阻斜坡对接焊过程的有限元模型,在相同参数下设计了工艺试验。分析了在不同的焊接工艺参数下,电阻斜坡对接焊的熔核形成过程与焊接过程的电场、温度场的关系,并通过对比金相试样与有限元模型运算结果验证了模型的准确性。结果表明:电阻斜坡对接焊的熔核为沿接触面生长的椭球形,工件厚度对熔核的生长方向起到了一定的导向作用,同时由于铝合金材料属性与焊接结构的不同,在焊接初期在下电极轴心处形成了一片电流集中区域。同时讨论了电流的最小压降原理在斜坡对接中的作用机理,为进一步研究电阻偏心点焊焊接过程积累基础科学数据。