An innovative joint interface design for reducing intermetallic compounds and improving joint strength of thick plate friction stir welded Al/Mg joints

Friction stir welding of dissimilar Al/Mg thick plates still faces severe challenges, such as poor formability, formation of thick intermetallic compounds, and low joint strength. In this work, two joint configurations, namely inclined butt(conventional butt) and serrated interlocking(innovative butt), are proposed for improving weld formation and joint quality. The results show that a continuous and straight intermetallic compound layer appears at the Mg side interface in conventional butt joint, and the maximum average thickness reaches about 60.1 μm.Additionally, the Mg side interface also partially melts, forming a eutectic structure composed of Mg solid solution and Al_(12)Mg_(17) phase.For the innovative butt joint, the Mg side interface presents the curved interlocking feature, and intermetallic compounds can be reduced to less than 10 μm. The joint strength of innovative butt joint is more than three times that of conventional butt joint. This is due to the interlocking effect and thin intermetallic compounds in the innovative joint.

Experimental Study on the Bending Properties of Grouting Butt Joints Reinforced by Steel Plate Embedded in Bamboo Tube

The construction of grouting butt joints of bamboo tubes is simple and efficient.However,when the joint is bent,the low tensile strength of the mortar easily leads to cracking of the mortar prior to the failure of the bamboo tube.In this paper,a comparative test of the bending capacity was performed on grouting butt joints reinforced by nonperforated,fully perforated,and semiperforated steel plates embedded in bamboo tubes to obtain the loaddisplacement curves and ultimate bearing capacity of various specimens.The strengthening effect of CFRP pasted on bamboo tubes was also studied.The results show that the opening at the end of the steel plate is beneficial to resist the slip between the mortar and steel plate,while the complete section in the middle of the steel plate is conducive to making full use of the tensile strength of the steel plate.Therefore,it is best to insert the semiperforated steel plate with openings in the end and without openings in the middle into the mortar to enhance the bending properties of the grouting butt joint,which can make the failure mode of the joint change from brittle failure of mortar to ductile compression failure of bamboo tube.In addition,pasting CFRP sheets on the external wall of the bamboo tube helps to reduce the tensile stress of the mortar,while increasing the width of the steel plate can increase the bending moment of inertia of the mixture of the steel plate and mortar.These two complementary measures are very effective in delaying the cracking of the bamboo tube and improving the bending capacity of the joint.

The ultimate strength of doubler plate reinforced Y-joints under compression loading

It is common practice in the offshore industry to solve the punching shear problem due to compression by using doubler plate. The finite-element method is a useful tool for studying this problem. The aim of this paper is to study the static strength of doubler plate reinforced Y-joints subjected to compression loading. The finite-element method is adopted in numerical parametric studies. The individual influences of the geometric parameters βand τd （doubler plate to chord wall thickness ratio） and ld/d1（dubler plate length to brace diameter ratio） on the ultimate strength are made clear. The results show the size of plate may have important effects on the strength of reinforced joints. It is found that the ultimate strength of Y-joints reinforced with appropriately proportioned doubler plates can be greatly improved nearly up tothree times to un-reinforced Y-joints.

Vacuum electron beam brazing technology and finite element analysis on temperature field of capillary to plate joint

Some parts with capillary to plate joint have important application in aerocrafi. Vacuum electron beam brazing （VEBB） technology is used to realize this jointing with capillaries. Firstly 3D finite element analysis model is built in this paper according to this special structure. And then ANSYS finite element analysis software is used to analyze brazing temperature field at different brazing parameters. The calculation results show that the temperature field of simulation has good agreement with that measured by experiment, which proves dependence of the model built in this paper. And also reference parameters could be provided for real brazing process through calculation in this model. Brazed joint of capiUary to plate with good performance is achieved using VEBB technology. The achievement of the study will be applied in aerocrafi in the future.

Performance analysis of the SAW joint of duplex stainless steel clad plate

Duplex stainless steel clad plate exhibits good performance and is relatively inexpensive,however,some difficulties must be overcome when welding different materials. In this study,submerged arc welding（ SAW） was used to weld Baosteel ship clad plates（ 2205 ＋ DH36）,and the performance of the welded joints was tested. The results indicate that the mechanical properties and the corrosion resistance of the welded joints meet the required specifications. The distribution of the main anti-corrosive elements and the phase ratio of the welded joint are analyzed,thereby indicating excellent uniformity and confirming that the welded joint is corrosion resistant.

Posterior Positioning of a Clavicle Hook Plate Is a Risk Factor for Acromial Fractures after Acromioclavicular Joint Dislocation

Purpose: Acromioclavicular (AC) joint dislocation is commonly treated using a clavicle hook plate (HP). However, previous reports have indicated that acromial fractures may occur after HP fixation. The purpose of this study was to identify risk factors for acromial fractures. Methods: A retrospective study was conducted on 39 patients with AC joint dislocation who were treated using clavicle HP fixation in our hospital between 2006 and 2017. Related parameters, including Rockwood classification, hook angle, the degree of reduction, the coverage of the hook under the acromion, and the anteroposterior position of the hook under the acromion, were evaluated to identify risk factors for acromial fractures. Results: The mean age of the participants was 51.7 (range 19 - 81) years;34 were men and 5 were women. Injury occurred on the right side in 18 patients and on the left side in 21. Injuries were categorized as follows: 24 were Rockwood type III, one was type IV, and 14 were type V. Four of the 39 patients (10%) experienced acromial fractures. Statistical analyses indicated that the degree of reduction at the final follow-up was moderately correlated with the Constant score. Posterior positioning of the hook was the only identified risk factor for acromial fractures. Hook angle and the degree of reduction at the time of surgery were not significantly associated with acromial fractures. Conclusions: Postoperative shoulder function was associated with the degree of reduction at the final follow-up, suggesting that anatomical reduction is recommended for AC joint dislocation. Posterior positioning of the hook is a risk factor for acromial fractures;however, clavicle HP fixation provides a positive outcome for AC joint dislocation. Therefore, careful positioning of the hook is required for preventing acromial fractures.

Plate reinforced square hollow section X-joints subjected to in-plane moment

The static test of 13 square hollow section(SHS) X-joints with different β and different types of plate reinforcement under in-plane moment in brace was carried out. Experimental test schemes, failure modes of specimens, moment-vertical displacement curves, moment-deformation of the chord, and strain strength distribution curves were presented. The effect of β and plate reinforcement types on in-plane flexural property of SHS X-joints was studied. Results show that punching shear of chord face disappears, brace material fracture appears and concave and convex deformation of chord decrease when either collar plates or doubler plates were welded on chord face. Moment-vertical displacement curves of all specimens have obvious elastic, elastic-plastic and plastic stages. As β increases, the in-plane flexural ultimate capacity and initial stiffness of joints of the same plate reinforcement type increase, but ductility of joints decreases. With the same β, the in-plane flexural initial stiffness and ultimate capacity of doubler plate reinforced joints, collar plate reinforced joints, and unreinforced joints decrease progressively. Thickness of reinforcement plate has no obvious effect on in-plane flexural initial stiffness and ultimate capacity of joints. As thickness of reinforcement plate increases, the ductility of reinforced X-joints decreases. The concave and convex deformation of every specimen has good symmetry;as β increases, the yield and ultimate deformation of chord decrease.

Numerical investigation on the position of holes for reducing stress concentration in composite plates with bolted and riveted joints

This paper studies the effects of fiber orientaion and holes position on stress concentration and the determination of weakened areas in the composite of glass fiber reinforced epoxy resin around the hole for joints by using the finite element method.In this study,for the observation of areas affected by stress concentration Tsai-Wu failure criterion is used to determine the failed elements and ANSYS Software is implemented for modeling.In order to compare the effect of geometric parameters on stress concentration around the holes,two types of hole position arrangement along with fibers orientation have been studied.Results show that the stress concentration coefficient is lower in the second type of holes arrangement in comparison with the first type for the same component dimensions.Increasing the distance from hole center to upper or lower edge of the sample and also decreasing the distance between holes,would result in an increase in the stress concentration.

Clinical study on treatment of TOSSY type III acromioclavicular joint dislocation with clavicular hook plate combined with coracoclavicular ligament repair

Objective:To explore the treatment of TOSSY type III acromioclavicular joint dislocation with clavicular hook plate combined with coracoclavicular ligament repair and its clinical effect.Methods:80 patients with TOSSY type III acromioclavicular joint dislocation who were admitted to our hospital from January 2014 to January 2019 were selected.They were randomly divided into the control group(n=39,treated with clavicular hook plate)and the observation group(n=41,treated with clavicular hook plate combined with coracoclavicular ligament repair)by the random number table method.The clinical efficacy in 12 months after operation,related clinical indicators,12-month postoperative recovery and postoperative complications were compared between the two groups.Results:The excellent and good rate was 92.68%(38/41)in 12 months after operation in the observation group,which was higher than that(76.92%,30/39)in the control group(p<.05).There were no significant differences in the duration of surgery,intraoperative blood loss and HLOS between the observation group and the control group(p>.05).In 12 months after operation,abduction activity and forward flexion activity of the observation group were higher than those of the control group,and visual analogue score(VAS)was lower than that of the control group(p<.05).The incidence of complications in the observation group was slightly lower than that in the control group,but there was no statistically significant difference between the two groups(p>.05).Conclusions:For TOSSY type III acromioclavicular joint dislocation,clavicular hook plate combined with coracoclavicular ligament repair has a good clinical efficacy.It can improve shoulder joint function,alleviate shoulder pain and have fewer complications.It can provide a reference for clinical treatment of this type of acromioclavicular joint dislocation.

Achieving high union rates after first metatarsophalangeal joint arthrodesis:Radiographic outcomes and technical pitfalls

BACKGROUND Fusion of the first metatarsophalangeal(MTP1)joint is a common surgery performed to correct hallux rigidus,hallux rigidus et valgus and other painful degenerative diseases of the MTP1.AIM To assess outcomes of our surgical technique including non-union rates,accuracy and aims of correction.METHODS Between September 2011 and November 2020 a total 72 of MTP1 fusions were performed using a low profile,pre-contoured dorsal locking plate and a plantar compression screw.Union and revision rates were analyzed with a minimum clinical and radiological follow up of at least 3 mo(range 3-18 mo).The following parameters were evaluated on pre-and postoperative conventional radiographs:Intermetatarsal angle,Hallux-valgus angle,dorsal extension of the proximal phalanx(P1)in relation to the floor and the angle between the Metatarsal 1 and the P1(MT1-P1 angle).Descriptive statistical analysis was performed.Pearson analysis was used to assess for correlations between radiographic parameters and achievement of fusion.RESULTS An overall union rate of 98.6%(71/72)was achieved.Two out of 72 patients did not primarily fuse with one patient suffering from a non-union,whilst the other demonstrating a radiological delayed union without clinical symptoms,with eventually complete fusion after 18 mo.There was no correlation between the measured radiographic parameters and the achievement of fusion.We believe the reason for the non-union was mainly attributed to the patient’s incompliance without wearing the therapeutic shoe leading to a fracture of the P1.Furthermore,we didn`t find any correlation between fusion and the degree of correction.CONCLUSION With our surgical technique,high union rates(98%)can be achieved using a compression screw and a dorsal variable-angle locking plate to treat degenerative diseases of the MTP1.

双切口双钢板内固定术对Schatzker V型胫骨平台骨折患者骨折愈合及关节稳定性的影响

目的探讨双切口双钢板内固定术对Schatzker V型胫骨平台骨折患者骨折愈合及关节稳定性的影响。方法回顾性分析2020年1月—2022年12月日照市人民医院收治的60例Schatzker V型胫骨平台骨折患者的临床资料,按手术方式不同将双切口双钢板内固定术治疗的30例患者设为观察组,将单侧锁定钢板固定术治疗的30例患者设为对照组。比较两组手术相关指标、膝关节功能、关节稳定性、日常生活能力、平衡能力、生活质量及并发症。结果两组患者手术时间、切口长度、术后住院时间比较,差异无统计学意义(P>0.05);观察组患者术中出血量、术后引流量多于对照组,骨折愈合时间短于对照组,差异有统计学意义(P<0.05);观察组患者术后3个月骨关节炎指数(WOMAC)中日常生活、疼痛、关节畸形及总分均低于对照组,差异有统计学意义(P<0.05);观察组患者术后3个月胫骨平台内翻角(TPA)、胫骨平台后倾角(PA)低于对照组(P<0.05);观察组患者术后3个月Barthel指数(BI)评分、Berg平衡量表(BBS)评分高于对照组,差异有统计学意义(P<0.05);观察组患者术后3个月世界卫生组织生活简易量表(WHOQOL-BREF)中生理、心理、社会及环境领域评分高于对照组,差异有统计学意义(P<0.05);两组并发症发生率比较,差异无统计学意义(P>0.05)。结论双切口双钢板内固定术治疗Schatzker V型胫骨平台骨折效果更佳,可提高关节稳定性,缩短骨折愈合时间,增强日常活动能力,安全可靠。

蜂窝梁H型柱绕弱轴向端板连接节点抗震性能研究

目的 提出一种蜂窝梁H型柱绕弱轴向端板连接节点,探究节点抗震性能及不同因素对其影响规律,为相关设计提供借鉴。方法 理论分析蜂窝梁H型柱绕弱轴向端板连接节点传力机制,建立并验证蜂窝梁H型柱绕弱轴向端板连接节点ABAQUS模型,研究端板厚度、开孔率对节点初始转动刚度、承载能力、耗能能力、延性、刚度退化及破坏形式影响规律。结果 蜂窝梁H型柱绕弱轴向端板连接节点弯矩最终由柱腹板与正向端板抗弯、柱翼缘与侧向端板抗剪承担;剪力最终由高强摩擦型螺栓连接面间摩擦力承担;端板厚度及开孔率越大,节点耗能进入蜂窝梁耗能阶段越早,连接刚度足够时节点抗震性能主要取决于蜂窝梁。结论 提出了蜂窝梁H型柱绕弱轴向端板连接节点弯矩路径传递分配系数计算方法,建议节点端板厚度应大于1倍柱翼缘厚度,开孔率取值为60%~65%。

单板焊接空心球节点受拉承载性能研究

单板焊接空心球节点常用做弦支穹顶上部结构连接拉杆或拉索的节点,单板主要承受拉力并传递至焊接空心球,为了满足工程设计的要求,需对其受拉承载性能进行研究.通过试验,研究了不同参数的单板焊接空心球节点轴拉状态下的受力性能和破坏机理,建立有限元模型并进行验证,该模型能较好地反映单板焊接空心球节点轴拉性能,通过有限元模型参数化分析揭示了节点尺寸、加劲肋、单板尺寸等参数对其力学性能的影响规律,并提出单板焊接空心球轴拉承载力计算公式.研究结果表明:单板焊接空心球在轴拉作用下为应力集中导致的剪切强度破坏,破坏发生在单板端部与空心球连接处,表现为焊接空心球被撕裂;有限元应力云图得出破坏时沿着单板平面内拉力方向的剪应力起主要作用;单板焊接空心球节点的受拉承载力随单板宽度及空心球壁厚的增大而明显增大,空心球直径的增大会使承载力略有降低,单板的厚度增加使节点承载力略有提高,单板的高度对节点承载力的影响较小,空心球内设置加劲肋能使承载力提高至少20%;基于参数化提出的单板焊接空心球节点的受拉承载力计算公式能简便地计算出单板焊接空心球节点的承载力,相对误差在±15%以内,满足工程设计误差要求.研究工作可为今后外接单板的焊接空心球节点分析设计提供参考.

微创经皮钢板内固定技术在锁骨中段粉碎性骨折锁定钢板固定术中应用

目的 探讨微创经皮钢板内固定(MIPPO)技术在锁骨中段粉碎性骨折锁定钢板固定术中的应用价值。方法 回顾性选取2020年6月—2022年6月130例锁骨中段粉碎性骨折的临床资料,根据手术方法分为观察组和对照组,每组65例。对照组行传统切开复位内固定,观察组行MIPPO技术联合锁定钢板治疗。比较2组围术期指标、并发症、手术优良率及手术前后疼痛应激介质、肩关节功能指标。结果 观察组切口长度、骨折愈合时间短于对照组,术中出血量少于对照组,术后1 d疼痛视觉模拟评分法评分低于对照组(P<0.01)。术后1 d,观察组血清P物质、前列腺素E_(2)低于对照组,β内啡肽高于对照组(P<0.05);术后3、6个月,观察组Constant-Murley肩关节功能评分及肩关节前屈、后伸、外旋活动度高于对照组(P<0.05)。观察组并发症总发生率低于对照组,术后6个月手术优良率高于对照组(P<0.05)。结论 MIPPO技术联合锁定钢板治疗锁骨中段粉碎性骨折能显著提高手术优良率,减少术中出血量,促进肩关节功能恢复,抑制疼痛因子释放,缓解术后早期疼痛,还能降低并发症风险。

基于新型耗能板提升钢框架节点抗震和抗连续倒塌能力

针对全焊节点在地震和连续倒塌条件下有限的抗倒塌能力,该文基于新型耗能板对其进行改进提升。首先通过试验、数值模拟和理论分析相结合的方法揭示了新型耗能板在单调荷载和循环荷载作用下的力学性能;进而通过新型耗能板与节点在地震作用和连续倒塌条件下的协同作用,给出了新型耗能板节点的设计方法。结果表明:新型耗能板在单调和循环荷载作用下的力学性能不同,在单调荷载作用下表现为受拉破坏,在循环荷载作用下表现为剪切破坏;通过算例分析表明,新型耗能板节点的抗震与抗连续倒塌设计方法是合理的;新型耗能板全焊节点在地震和连续倒塌条件下主要经历双塑性区域形成阶段和硬化阶段,其中新型耗能板全焊节点的抗震和抗连续倒塌性能的差异主要体现在硬化阶段;新型耗能板的增加可同时有效提高全焊节点在地震和连续倒塌条件下的承载力、变形和耗能能力。

叠合板式综合管廊侧墙连接节点面外抗震性能试验研究

叠合板式综合管廊属于半装配式结构,其接缝数量少,抗渗性能优越,应用前景广泛。为了研究采用灌浆套筒连接和浆锚搭接连接两种连接方式的叠合板式综合管廊侧墙在面外荷载作用下的抗震性能,该文开展了采用两类连接方式的足尺侧墙模型的面外低周反复试验,并与管廊现浇侧墙构件作对比。通过分析试件破坏模式、裂缝分布以及受力性能指标,初步揭示了不同连接方式对叠合板式侧墙面外抗震性能的影响。研究表明:叠合板式试件与现浇试件抗震性能基本一致,滞回曲线均较饱满,极限承载力与刚度退化规律基本一致,满足装配式结构等同现浇的抗震设计要求;两类叠合板式管廊侧墙试件延性系数分别为7.05和8.50,均具有良好的面外延性,满足我国抗震设计规范中变形能力要求;采用浆锚搭接连接的叠合板式试件与采用灌浆套筒连接的叠合板式试件相比,滞回曲线更加饱满,变形能力好,但峰值抗侧承载力低,相同侧向位移下损伤破坏严重;两种连接方式的均可有效传递钢筋应力直至构件破坏。

TightRope带襻钢板与Endobutton钢板治疗肩锁关节脱位的疗效比较

目的比较TightRope带襻钢板与Endobutton钢板在治疗肩锁关节脱位中的疗效。方法回顾性分析2021年3月~2023年2月常州市第二人民医院创伤中心94例肩锁关节脱位的临床资料,根据时间段分为2组,2021年3月~2022年2月采用Endobutton钢板治疗(E组,n=47),2022年3月~2023年2月采用TightRope带襻钢板治疗(T组,n=47),末次随访比较2组围术期指标、疼痛视觉模拟评分(Visual Analogue Scale,VAS)、Constant-Murley肩关节功能评分及手术并发症发生率。结果T组手术时间、术中出血量、切口长度及术后7 d VAS评分明显短于/低于E组(P<0.05)。2组神经损伤、内固定移位、锁骨骨折、血管损伤及感染发生率无统计差异(χ~2=1.389,P=0.239)。2组术后9个月肩关节功能主客观评分与术前比较均得到明显改善(均P=0.000);术后9个月肩关节功能主客观评分2组比较差异无显著性(P>0.05)。结论TightRope带襻钢板和Endobutton钢板治疗肩锁关节脱位均效果显著,可有效改善患者肩关节功能。与Endobutton钢板比较,TightRope带襻钢板手术创伤更小,出血更少,明显减轻术后疼痛,更有利于患者早期功能锻炼。

单一小切口带袢钛板与锁骨钩板内固定治疗Rockwood Ⅲ型肩锁关节脱位的临床疗效

【目的】探讨单一小切口带袢钛板与锁骨钩板内固定治疗RockwoodⅢ型肩锁关节脱位的临床效果。【方法】回顾性分析本院2018年1月至2021年1月收治的33例RockwoodⅢ型肩锁关节脱位患者,根据治疗方法不同分为对照组(采用锁骨钩板内固定治疗,n=17)和观察组(采用带袢钛板内固定治疗,n=16)。比较两组手术时间、住院天数、术中失血量、手术切口长度、肩部疼痛视觉模拟评分法(VAS)评分、术后并发症、肩关节功能Constant-Murley评分。【结果】观察组患者住院时间、手术切口长度短于对照组,术中出血量少于对照组,差异均有统计学意义(P<0.05)。观察组术后7 d、30 d、90 d、180 d及最后随访时肩部疼痛VAS评分均低于对照组,肩关节功能Constant-Murley评分优于对照组,差异均有统计学意义(P<0.05)。观察组并发症发生率为12.5%(2/16),显著低于对照组的52.9%(9/17),差异有统计学意义(P<0.05)。【结论】单一小切口带袢钛板内固定治疗RockwoodⅢ型肩锁关节脱位术后并发症少、创伤小、肩关节功能恢复快,值得临床推广应用。

CFRP-木结构波纹钢填板螺栓节点力学性能正交试验研究

为了明确异型截面钢填板对节点性能的影响,为木结构异型钢填板螺栓节点提供安全性的设计经验,提出CFRP-木结构波纹钢填板螺栓节点,在正交试验设计条件下开展单轴顺纹拉伸试验研究.试验发现,节点具有多种受力特征,包括木构件剪切破坏、顺纹向张开型断裂(TL断裂)、端部顺纹压溃、CFRP断裂和螺栓弯折等形式;节点在受力过程中没有明显屈服阶段,主要经历线弹性阶段、断裂失效过渡阶段和断裂失效阶段.通过正交参数分析得到不同因素对所提节点主要力学性能的影响程度及规律.结果表明:各因素对极限强度和延性的影响比对弹性刚度的影响显著,且波角和波高为主要影响因素.极限强度与波角负相关且随着波高的增大呈波动变化,延性与波角和波高负相关.

壁式钢管混凝土柱-钢梁嵌入式双侧板节点抗震性能研究及设计建议

以壁式钢管混凝土柱-钢梁嵌入式双侧板节点为研究对象,进行两个足尺试件的拟静力试验,分析节点的破坏模式、滞回曲线、骨架曲线,并研究节点承载力、延性、耗能能力和刚度退化等指标。试验结果表明:试件破坏模式分别为侧板外梁端形成塑性铰、节点核心区侧板开裂及轻微鼓曲;试件滞回曲线稳定饱满,曲线呈现梭形,试件延性系数为3.11~3.53,等效黏滞阻尼系数大于0.4,具有良好的耗能能力;刚度退化较稳定,具备较好的抗侧能力。在验证有限元模型合理的基础上,通过有限元变参分析此类节点的滞回性能,结果表明:增加侧板厚度或侧板外伸长度可提高嵌入式双侧板节点的承载力及延性。最后结合试验和有限元变参分析结果,针对此类节点提出设计建议。