IVOSTUD螺柱焊异常横焊缺陷分析及优化

螺柱焊技术作为一类将螺柱或柱状金属焊接在金属表面的特种焊接工艺方法,在汽车生产制造中有广泛应用,在一些豪华车上通过螺柱焊焊接的螺柱数量高达三四百颗。文中针对艾沃斯达特(IVOSTUD)公司的螺柱焊枪进行研究,结合北京奔驰汽车车身生产过程中使用该设备进行螺柱焊接产生的一系列问题进行系列化的研究分析和模拟测试,对设备遇到的诸多问题提出有效解决方案,并具体到现场实施,经过一段时间的验证被证明有效。文中是对以上模拟测试过程和研究分析结论进行的总结提炼,一方面是与使用此螺柱焊枪的其他同行进行经验分享和技术交流,另外文中所采用的问题解决分析策略和试验验证测试手段亦值得与生产制造相关的技术工程师做参考借鉴和交流讨论。

Investigation on the stepping arc stud welding process

Through the investigation on traditional arc stud welding process, a new welding gun and its control system were developed in this paper. The stepping arc stud welding gun was mainly made by a stepping motor as actuating unit and a screw-driven device as moving unit. A control system with a MCS-51 single-chip microcomputer as main control component was used to realize the new stud welding procedure. This new welding process with stepping stud welding gun is named as stepping arc stud welding. In the new welding process, the stud action can be looked as constituted by some micro steps. The setting and adjusting of the stepping arc welding gun behavior parameters are accomplished independently. It is indicated from the results of process tests and bending test that the stepping arc stud welding process is practicable.

Microstructure characteristics and mechanical properties of steel stud to Al alloy by CMT welding-brazing process

Cold metal transfer （CMT） welding of nickel-coated Q235 steel studs with 606l Al alloy was carried out using ER4043 as filler metal. The welding process was stable, and appearance of weld formed well without surface defect under the parameters of welding current 121 A, welding voltage 15.4 V and welding speed 6 r/min. The microstructure of fiUer metal was analyzed by means of scanning electron microscopy. The filler metal and 6061 Al alloy were fused to form fusion welding interface, the fusion zone had a good bonding without any micro defect. The steel stud did not melt and brazing interface was formed between the filler metal and steel stud. Two different reaction layers existed in the brazing interface, the Fe2Al5 layer about 10 -12 p^m formed near the steel stud side, and the other layer was mainly composed of FeAl3. Nickel-rich zone was formed in the root toe area of the fillet weld, which was mainly composed of Al3Ni2. The tensile tests showed that the maximum shearing strength of the joints was 129 MPa. The joint was brittle fractured in the intermetallic compound layer where plenty of FeAl3 were distributed continuously.

Mechanical performance of shear studs and application in steel-concrete composite beams

This work experimentally investigates the effects of shear stud characteristics on the interface slippage of steel-concrete composite push-out specimens. ABAQUS is used to establish a detailed 3D finite element(FE) model and analyze the behavior of push-out specimens. The modeling results are in good agreement with the experimental results. Based on parametrical analysis using the validated FE approaches, the effects of important design parameters, such as the diameter, number, length to diameter ratio, and yield strength of studs, concrete strength and steel transverse reinforcement ratio, on the load-slip relationship at the interface of composite beams are discussed. In addition, a simplified approach to model studs is developed using virtual springs with an equivalent stiffness. This approach is demonstrated to be able to predict the load-displacement response and ultimate bearing capacity of steel-concrete composite beams. The predicted results show satisfactory agreement with experimental results from the literature.

Nickel-coated Steel Stud to Aluminum Alloy Joints Made by High Frequency Induction Brazing

Nickel-coated 45 steel studs and 6061 aluminum alloy with 4047 A1 alloy foil as filler metal were joined by using high frequency induction brazing. The microstrueture of Fe/A1 brazed joint was studied by means of optical microscopy （OM）, scanning electron microscope （SEM）, energy dispersive X-ray （EDX）, and X-ray diffraction （XRD）. Results showed that 45 steel stud and 6061 aluminum alloy could be successfully joined by high frequency induction brazing with proper processing parameters. The bonding strength of the joint was of the order of 88 MPa. Ni coating on steel stud successfully avoided the generation of Fe-AI intermetallic compound which is brittle by blocking the contact between A1 and Fe. Intermetallic compounds, i e, AI3Ni2, AlmNi0.9 and A10.3Fe3Si0.7 presented in AI side, FeNi and Fe-A1-Ni ternary eutectic structure were formed in Fe side. The micro-hardness in intermetallic compound layer was 313 HV. The joint was brittle fractured in the intermetallic compounds layer of A1 side, where plenty of A13Ni2 intermetallie compounds were distributed continuously.

Design and Implementation of Stud-farm Daily Management System Based on C/S Structure

In order to achieve the computerization and digitization of the daily system of stud-farm, the immunization system technology, racecourse health monitoring technologies and the stud-farm prevention technologies were combined to built the studfarm daily management system. By using Visual Studio 2008 and Microsoft Office Access 2003, an immunization information system was developed based on Client/Server structure and combined with the key immunization link of horses. The system included studfarm immune management and racecourse health monitoring system. The immune management contained immunization information input, the inquiry of immunization information, immunization statistics, immunization-reminding and system management. The racecourse health monitoring system included stud-farm monitoring, horses monitoring and inquiry and statistics of health monitoring. The software realized the analysis and tips of the daily information in stud-farm. The software could record the appropriate data and carry on the statistics. The stud-farm daily management system greatly improved the efficiency of the expanded program about immunization and horses＇ healthy rearing technique.

Design methods of headed studs for composite decks of through steel bridges in high-speed railway

Aimed at two typical composite floor systems of through steel bridges in high speed railway,design methods of headed studs were put forward for different composite members through comparing and analyzing the structure,mechanical characteristics and transmission routes of deck loads.The simplified calculation models were brought out for the stud design of the longitudinal girders and transverse girders in the composite floor system of Nanjing Dashengguan Yangtze River Bridge (NDB).Studs were designed and arranged by taking the middle panel of 336 m main span for example.The results show that under deck loads,the longitudinal girders in the composite floor system of through steel bridges are in tension-bending state,longitudinal shear force on the interface is caused by both longitudinal force of "The first mechanical system" and vertical bending of "The second mechanical system",and studs can be arranged with equal space in terms of the shear force in range of 0.2d (where d is the panel length) on the top ends.Transverse girders in steel longitudinal and transverse girders-concrete slab composite deck are in compound-bending state,and out-of-plane bending has to be taken into account in the stud design.In orthotropic integral steel deck-concrete slab composite deck,out-of-plane bending of transverse girders is very small so that it can be neglected,and studs on the orthotropic integral steel deck can be arranged according to the structural requirements.The above design methods and simplified calculation models have been applied in the stud design of NDB.

Comparison of Studs and Perfo-Bond Strips on Mechanical Behavior of Composite Girders under Negative Bending

The purpose of the present study is to investigate the influence of different types of shear connectors on mechanical behavior of composite steel and concrete girders under negative bending moment. Two overturned simply supported steel-concrete composite girders with different shear connectors including studs and PBLs （perfo-bond strips） were tested under point load in the mid-span. Based on the experimental observations, a three-dimensional FE （finite element） model capable of analyzing the composite girders subjected to negative bending moment was built. Load and deformation response, concrete initial cracking and composite girder ultimate load bearing capacity, strain development process of reinforcing bars before and after concrete cracking were observed in the test and compared with the numerical values. Results predicted by this modeling method are in good agreement with those obtained from the tests. Furthermore, the %rack closure＂ or ＂through crack＂ load were recorded by π-ganges in the tests and compared with the code-specified ultimate load.

Stud Pose Detection Based on Photometric Stereo and Lightweight YOLOv4

There are hundreds of welded studs in a car.The posture of a welded stud determines the quality of the body assembly,thus affecting the safety of cars.It is crucial to detect the posture of the welded studs.Considering the lack of accurate method in detecting the position of welded studs,this paper aims to detect the weld stud’s pose based on photometric stereo and neural network.Firstly,a machine vision-based stud dataset collection system is built to achieve the stud dataset labelling automatically.Secondly,photometric stereo algorithm is applied to estimate the stud normal map which as input is fed to neural network.Finally,we improve a lightweight YOLOv4 neural network which is applied to achieve the detection of stud position,thus overcoming the shortcomings of traditional testing methods.The research and experimental results show that the stud pose detection system designed achieves rapid detection and high accuracy positioning of the stud.This research provides the foundation combining the photometric stereo and deep learning for object detection in industrial production.

Current waveforms and sequence control system of microprocessor-controlled short cycle stud welding converter

The applied conditions of stud welding on body of automobile, and the current waveforms and sequence control techniques which are set to meet the quality of stud welding in the car body, are introduced in this paper. The realizing method of current waveforms and sequence control based on microprocessor are also discussed in detail. The waveforms of output welding current and voltage are measured. It is proved that the techniques including current waveforms & sequence control can successfully meet the demand of automobile stud welding.

Double⁃Shear Experiments of Cold⁃Formed Steel Stud⁃to⁃Sheathing Connections at Elevated Temperatures

The behavior of cold⁃formed steel(CFS)stud⁃to⁃sheathing connections at elevated temperatures is an important parameter for the fire resistance design and modeling of mid⁃rise CFS structures.In this paper,three kinds of sheathings,namely,medium⁃and low⁃density calcium⁃silicate boards and oriented strand board,were selected for double⁃shear experiments on the mechanical properties of 253 screw connections at ambient and elevated temperatures.The effects of the shear direction,screw edge distance and the number of screws on the behavior of the connections were studied.The results showed that the shear direction and the screw edge distance more significantly influenced the peak deformation,while their impacts on the peak load varied with the type of sheathings.Compared with the single⁃screw connections,the peak loads of the specimens with double⁃screw connections obviously increased but did not double.Finally,a simplified load⁃displacement curve model of stud⁃to⁃sheathing connections at elevated temperature was generated first by establishing the prediction formula for characteristic parameters,such as the peak load,the peak deformation and the elastic stiffness,and then by considering whether the curves corresponded to stiffness increase phenomena.The present investigation provides basic data for future studies on the numerical modeling of CFS structures under fire conditions.

联邦德国带端头锚杆(Stud)的新设计方法及算例

结合梁中采用带端头的锚杆作为联结件已很普遍。最近联邦德国根据试验研究对此建立起在受拉、受剪和剪拉组合等外力作用下的计算方法,规定了锚杆边距、中距以及锚固在受拉区或受压区,锚杆群等因素对承载力的影响,较以往的设计方法有所改进。本文所介绍的这一方法已得到联邦德国政府建设技术院审定批准,文末附有简明的设计算例。

Home Studìo(三)

Track 4音频软件 前面说完了硬件,这次当然就是要说说软件了. 经常用到的音频软件,笔者的观点可以将其分为以下几类(可能不是太科学):多轨音频软件、wav编辑软件、效果器插件、软音源(软采样器)以及各种其它的周边工具软件.严格地说软音源应该算在MIDI软件之中;还有一些集大成者被称作音频工作站软件,不仅上面提到的几类软件功能通通囊括,还有强大的MIDI音序器功能(即录制/编辑MIDI文件),甚至还可以刻录CD,可算是音乐软件里的航空母舰了. 废话就不多说了,还是让我们走近些来看仔细吧.

Dragon Brand Steel Stud

The Dragon Brand light steel stud used for partition is a kind of metallic framework that is continuously milled and rolled with cold formed steel shape using a cold-worked steel plate or strip, or zinc-coated plate or strip, or coloured plastic packing steel plate, as materials. The steel stud has the features of light weight, high tension and anti-erosion. It can be used as light partition material together with plaster board, and its products or with other board materials such as GRC boards or

Attempt to improve Vocabulary Teaching for Higher Vocational College Students

Vocabulary is the building material of language,and vocabulary study is therefore one of the most important aspects in any language learning.It is a key point to improve English learning through paying more attention to vocabulary acquisition.However,vocabulary teaching is one aspect of language teaching that has not been given enough attention in China.Therefore,some issues in vocabulary teaching and learning in higher vocational colleges are being addressed at present,which are worthy of our further consideration.

Stud welding for fixation of cryogenic insulation of membrane tanks in LNG ship building

The support plates including all of the inner hulls such as E grade steel, weld seams and SUS304L were considered to establish the optimal stud welding condition in LNG ship building. The stainless steel plate was especially applied to the bracket on the liquid dome. The polished and etched surfaces of the welded stud and support plate were examined if the bead was properly formed. With the micrographic examination, the fusion boundary of metal weld zone formed by stud welding was analyzed to optimize the welding parameters. And also the analysis of the unacceptable welding faults such as cold and hot weld were performed. The mechanical tests such as tensile tests and bending tests were carried out to reveal any abnormal variation in the relationship of process parameters and the strength.

Towards experimental studying the airborne sound insulation of light frame walls with staggered studs

Light frame walls(LFWs) serve as common partition walls in prefabricated buildings due to their lightweight nature, costeffectiveness, energy efficiency, and adaptability for rapid on-site assembly. However, their acoustic insulation capability is hindered by issues such as sound bridges, resonance, and coincidence dips, resulting in inadequate sound insulation. This study aims to propose LFW designs with superior acoustic insulation suitable for practical engineering while meeting prevailing national standards. Nine full-scale LFW configurations were subjected to laboratory testing to evaluate the impact of staggered stud arrangements, stud types, and incorporation of compounded materials. The tests were performed between 100 and 5000 Hz,and the sound pressure level and reverberation time at 1/3 octave band were measured and used to calculate the weighted sound insulation index(Rw). Results demonstrated that the outlined design modifications significantly enhanced the sound insulation of the LFW. These modifications effectively mitigate the influence of sound bridges while addressing resonance and coincidence dips inherent in the wall system. Particularly noteworthy was the superior sound insulation achieved by staggered-stud LFWs with compounded materials, surpassing that of autoclaved lightweight concrete walls commonly used in prefabricated constructions despite having lesser thickness and surface density. Rwvalues increased from 43 to 54 dB compared to conventional LFWs, translating to a notable elevation in airborne sound insulation level from 4 to 7 as an internal separation component,meeting the requisite standards for most applications.

钢-UHPC轻型组合结构短栓钉抗剪性能试验研究

通过6个钢-超高性能混凝土(ultra-high performance concrete,UHPC)轻型组合结构短栓钉推出试验,对其抗剪承载力、破坏形态、栓钉应变及荷载-滑移曲线进行了研究,探讨了栓钉直径、长度、数量以及界面黏结对短栓钉抗剪性能的影响规律.结果表明:所有试件均为栓钉根部剪切破坏,UHPC板除栓钉根部沿承压方向部分UHPC压碎外,其余部分保持完好,UHPC可以抵抗栓钉传递的高压应力;栓钉根部截面屈服后应力强化阶段明显,栓钉发生剪切破坏时,栓钉根部上侧应变超过3500με;长径比为2.0的短栓钉在UHPC中也能发挥全部强度;所有试件的荷载-滑移曲线分为弹性、弹塑性和塑性3个阶段,所有短栓钉的最大滑移量均小于4 mm,工程应用时应按照弹性剪力连接件进行设计;栓钉直径对栓钉抗剪性能提高最显著,直径16 mm的栓钉比直径13 mm的栓钉的抗剪承载力和极限滑移分别提高了46.4%和11%,弹性刚度和塑性刚度分别提高了35.8%和59.1%,增加栓钉长度和界面黏结能有效提高栓钉的剪切刚度,长径比为3.0的栓钉比长径比为2.5的栓钉的弹性刚度提高了12.3%,界面有黏结试件比界面无黏结试件的弹性刚度提高了17.4%;相同间距内,合理增加更多栓钉有利于提高整体抗剪强度,但会降低延性变形能力.最后,结合实验数据和国内外UHPC中栓钉推出试验结果,建立了UHPC中栓钉荷载-滑移曲线和抗剪承载力预测表达式,计算值与试验值吻合良好.

论新中国史研究与“新中国学”

今年是中华人民共和国成立75周年。75年来特别是中共十八大以来,中国特色社会主义进入新时代,党领导人民全面建成小康社会,乘势开启实现第二个百年奋斗目标新征程。新中国的历史发展,是历史中国的延续和发展,中国式现代化由奠基、开创到深化和拓展,中华民族从站起来到富起来再到强起来,中华文明实现生命更新和现代转型。新中国的历史发展,不断孕育、生成和发展关于新中国的认识和研究,即“新中国学”。“新中国学”特指关于中华人民共和国之学,由此也推动中国学从“他塑”转向“自塑”,重心从研究中国传统历史文化转向探讨关于新中国的历史、社会和时代发展,以及新中国与世界的关系。“新中国学”是一个复杂的系统学科,是关于新中国的“百科全书”;作为世界中国学的重要组成部分,在向世界传播中国精神、中国价值、中国力量方面发挥着重要作用。加快构建“新中国学”的学科体系、学术体系和话语体系,推动引领世界中国学发展,是推进新中国史研究的学科建设要求,也是推动哲学社会科学讲好中国故事、传播好中国声音的时代要求。为此,我们与河北学刊杂志社共同策划了本组专题讨论,重点以《论新中国史研究与“新中国学”》《新中国史史料学的新境遇与新问题--兼论“新中国学”资料构建的发展性与实践性》为题作多方面探讨,以期引领和推动“新中国学”研究不断向纵深发展。

不同锈蚀程度下栓钉连接件的抗剪性能分析

为研究栓钉连接件锈蚀条件下的抗剪性能退化规律,建立ABAQUS有限元模型进行数值模拟.针对均匀圆环、受压区半环、受拉区半环及拉压区半环4种不同的锈蚀分布形态,考虑不同的锈蚀高度、锈蚀深度进行数值分析.结果表明,当锈蚀深度相同时,4种锈蚀分布形态的栓钉抗剪承载力随锈蚀高度的增加而降低,在锈蚀高度为10 mm时降到最小,且锈蚀深度越大,承载力降低程度也越大;当锈蚀高度相同时,随着锈蚀深度的增加,抗剪承载力和抗剪刚度基本上呈线性下降趋势;当锈蚀高度和深度相同时,均匀圆环锈蚀的抗剪承载力和刚度的降低程度最大,相比其他3种情况降低60%左右,受压区半环锈蚀的抗剪承载力和刚度的降低程度最小.研究成果可为钢混组合结构栓钉连接件耐久性设计提供参考.