弯曲载荷下特殊螺纹接头性能有限元分析

利用有限元模型分析弯曲载荷下特殊螺纹接头的结构、密封及抗疲劳性能,并详细说明了相关评价方法.分析认为,特殊螺纹接头在弯曲载荷下的不同位置存在应力状态的差异;随着弯曲度的增加,拉伸面一侧的密封强度下降,压缩面一侧的密封强度增强;该特殊螺纹接头易产生疲劳破坏的最危险区域为接箍泄油槽处.     

台肩角度对特殊螺纹接头密封性能的影响

利用有限元软件对-15°台肩、-5°台肩和直角台肩3种特殊螺纹接头,在上扣、上扣+拉伸和上扣+压缩条件下进行模拟计算。根据模拟计算结果分析得出:在上扣过程中,台肩角度变化对特殊螺纹接头密封面处密封性能影响很大,而对台肩辅助密封性能影响不大;在上扣+拉伸载荷条件下,台肩角度变化对接头密封面处的接触应力影响不大,而台肩的辅助密封性能随着管端与台肩的脱离分开而失效;在上扣+压缩载荷条件下,-15°台肩接头密封面的密封性能最佳,压缩载荷对台肩辅助密封性能影响不大。     

CBFJ直连型特殊螺纹接头设计分析

介绍直连型特殊螺纹接头CBFJ的结构特点,利用有限元分析的方法,对该接头在服役过程中的典型工况进行分析;重点研究该接头的连接效率以及在复合载荷工况下的密封性能,并介绍其全尺寸试验结果。试验结果表明:CBFJ直连型特殊螺纹接头的连接效率达到管体强度的58%以上,在拉伸、压缩、内外压等复合载荷作用下,接头接触应力虽有显著变化,但保持了较高的密封指数,说明接头仍能保持良好的密封性能。     

模拟工况下特殊螺纹密封特性的有限元分析

借助ABAQUS有限元分析软件,对模拟工况下的常用特殊螺纹接头密封特性进行有限元分析,重点研究了该特殊螺纹接头在螺纹拧紧、拉伸、内压以及温度复合条件下的密封性能。结果表明:该特殊螺纹接头在服役环境下,密封面始终可以保持较高的接触应力,且等效VME应力最大值小于该材料的屈服强度,可有效减小接头在服役时发生泄漏或黏结的可能性。     

套管特殊螺纹接头性能有限元仿真分析

利用全尺寸实物试验和有限元仿真方法,研究Ф244.48 mm×11.99 mm规格HSM-2特殊螺纹P110套管的接头性能。结果显示:有限元计算时,在ISO 13679∶2002标准CAL IV A系试验所有加载点下,HSM-2特殊螺纹接头主密封面均保持较大接触压力和密封长度,密封指数较高;实物试验及有限元计算结果均证明了该接头具有可靠的密封性能和连接强度;有限元计算扭矩与实物试验扭矩能较好地吻合。     

弧形螺纹套管接头的设计及应力分析

提出了API长圆螺纹套管接头的弧形设计思想;通过有限元分析,比较了圆锥螺纹和弧形螺纹的螺纹接触应力分布。计算分析表明:弧形螺纹能优化接触应力分布,既容易加工、不增加成本,又能减少螺纹黏结的发生,提高套管使用寿命。     

TP-NF/E特殊间隙接箍接头的开发

针对页岩气井的井身结构特点及其对特殊螺纹的使用需求,研制开发了一种TP-NF/E特殊间隙接箍接头。介绍了Φ139.7 mm×10.54 mm规格P110 TP-NF/E特殊螺纹接头的开发情况;运用有限元分析和ISO13679∶2002 CAL II实物性能试验,评价了TP-NF/E特殊螺纹接头的抗螺纹黏结性能、密封完整性、结构完整性等。分析认为:该特殊螺纹采用勾型螺纹连接、锥-锥金属密封面、止扭矩台肩的形式设计,具有良好的抗螺纹黏结和密封性能、较大的抗弯曲能力、较高的抗压缩能力,达到了产品设计要求     

基于ABAQUS特殊螺纹接头的螺纹参数优化设计

利用ABAQUE有限元仿真软件分析Ф244.48 mm×11.99 mm规格某特殊螺纹接头,研究不同螺纹参数对其结构完整性和密封完整性的影响,并优化特殊螺纹接头参数。优化后的特殊螺纹接头参数为:螺距4～5牙/in,承载面角度-4°～-3°,导向面角度10°～25°,鼻端长度13～20 mm,密封面采用锥面/弧面配合。分析认为:优化后的螺纹接头模型具有良好的连接强度和优异的密封性能,其螺纹接头性能优于国内某特殊螺纹接头和国际某典型特殊螺纹接头。     

螺纹过盈量对特殊螺纹接头性能的影响

运用ABAQUS软件计算了在上扣、上扣+拉伸条件下Φ139.70 mm×9.17 mm规格P110钢级特殊螺纹不同螺纹过盈量对接头性能的影响。模拟结果表明:上扣后,当螺纹过盈量∧0.159 0 mm时,密封面处接触压力变化不大;当螺纹过盈量∧0.238 5 mm时,随着螺纹过盈量的增加,密封面接触压力下降明显。上扣+拉伸条件下,随着螺纹过盈量的增加,密封面接触压力下降,同时接触位置向台肩处移动;当螺纹过盈量∧0.079 5 mm时,拉伸失效断裂在螺纹处;当螺纹过盈量∧0.159 0 mm时,拉伸失效断裂在管体。     

G3耐蚀合金油管特殊螺纹接头TP-G2的设计与开发

介绍G3耐蚀合金油管特殊螺纹接头TP-G2的设计开发情况。运用有限元分析结合全尺寸实物试验,建议TP-G2采用负角度偏梯形螺纹设计,且其内螺纹齿高略高于外螺纹,合理的密封面角度和密封过盈量配合,并在接箍中部设计有负角度扭矩台肩,对内外螺纹采用镀铜或喷砂处理,以保证接头具有良好的抗螺纹黏结能力,以及在复合载荷下具有优异的气密封能力。生产应用实践表明:设计开发的特殊螺纹接头TP-G2具有良好的抗螺纹黏结性能、密封性能,和较大的抗弯曲能力及较高的抗压缩能力,使用可靠。     

有限元模拟在泡沫铝力学性能研究上的应用现状与展望

有限元法是工程领域中应用最广泛的一种数值计算方法,从力学分析问题的角度来看,已在弹性静力学问题、动力学问题、弹塑性与接触力学、蠕变、疲劳与断裂力学、流体力学和热力学等领域得到广泛的应用。泡沫铝材料的力学性能主要包括压缩性能、拉伸性能、弯曲性能、冲击性能、吸能性等。本文详细叙述了有限元模拟泡沫铝压缩性能的现状及成果,简单介绍了模拟泡沫铝弯曲性能和吸能性的现状和成果,最后针对现状提出了自己的观点和看法。     

Bendability of aluminiumand steel-clad chromium plates

The present paper describes how the cladding of chromium plate with dissimilar metals improves the plastic bendability of the chromium. Three-point bending tests at various temperatures were performed for three types of chromium specimens: a monolithic chromium plate, aluminium- and steel-clad chromium plate. The aluminium-clad chromium plate was bent at 343 K up to a bent angle of 90 degrees without failure, even when the chromium layer was located outside of the plate (tension side), while the monolithic chromium plate could be bent exclusively at temperatures above 403 K. When the chromium layer was located inside of the steel-clad chromium plate (compression side), the plate was successfully bent at 307 K. The FE stress analysis of bending proved that the cladding of chromium plates with proper metals of different kinds is effective to reduce the tensile stress in chromium induced during bending and also the residual stress existing after bending operation.     

汉廷特殊螺纹接头油套管的技术特点与应用分析

介绍了汉廷特殊螺纹接头油套管系列产品的概况,在对汉廷典型特殊螺纹接头的技术特点进行系统分析的基础上,提出了关于不同设计类型特殊螺纹接头油套管适用工况的建议。简要介绍了汉廷特殊螺纹接头在中石化西南油气分公司的应用情况。     

AZ31B镁合金板材折弯过程中性层偏移规律研究

有效预测和评估板材变形程度对折弯成形工艺和产品精度控制有着现实的指导意义,且中性层偏移是衡量折弯板材拉压区域不均匀变形程度的重要参数。依据塑性变形理论中微元体应力平衡条件,基于能够体现镁合金拉压不对称性的Yoon2014屈服准则,得到了AZ31B镁合金板材折弯过程中中性层偏移量计算模型,并辅以有限元模拟和相应实验对中性层偏移模型进行验证。结果表明：所建立模型能够对镁板中性层偏移现象进行可靠预测,镁板在折弯过程中,受拉压不对称性的影响,中性层向拉伸侧偏移;折弯后角度越小,中性层偏移量越大,在折弯角度至90°,压下量为40～47 mm之间时的中性层偏移程度最明显。     

Reverse effect of tensile force on sidewall curl for materials with tensile/compressive strength difference

Sidewall curl occurring by the removal of tool surfaces after forming is one adverse phenomenon that should be effectively reduced in sheet metal forming operations. Among several process parameters controlling sidewall curl, a constraint tensile force is widely used along with attainable formability by introducing blank holder and drawbead. The classic but common knowledge is that sidewall curl is suppressed for conventional sheet metals as the constraint tensile force increases. Interestingly, however, for magnesium alloy sheets that have unusual asymmetry in tension and compression it has been recently reported that springback increases as the tensile force increases within a specific range of tension. The major deformation in the sidewall usually consists of bending and unbending under tensile force. Therefore, this unique stress-strain response of sheet materials with strength-differential, including magnesium alloys, should be considered for an accurate estimation of sidewall curl. In the present study, a semi-analytical bending/unbending theory incorporating characteristic constitutive behavior of magnesium alloys was developed to evaluate the moment-curvature relationship for various levels of constraint tensile forces. The present analysis proved that the reverse effect of constraint tensile force on sidewall curl was caused by the lower resistance to plastic yielding in compression with proper combination of applied tensile force.     

Analysis of the Mechanical Properties of an Arc Sprayed WC-FeCSiMn Coating: Compression, Bending, and Tension Behavior

This paper is concerned with the elastic and plastic forming behavior of arc sprayed WC-FeCSiMn coatings. The mechanical properties were investigated by indentation, bending, and tensile tests. These were performed on coated mild steel substrates as well as spark eroded and ground freestanding coatings with different geometries. The results of the indentation, bending, and tensile tests were evaluated concerning the coating microstructure, element, and pore distribution, as well as the local microhardness. The critical role of pores and inhomogeneities within the sprayed coating was examined in detail. Micro- and macrocracking were investigated by scanning electron microscopy after the indentation and tensile tests. It was figured out that the WC-FeCSiMn coating featured a distinctive brittle behavior. During the bending and tension tests, brittle forced fracture of the layer appeared almost without plastic deformations. A significant difference was determined between the compression and tensile performance of the coating. For instance, the Young??s modulus for compression strains was measured to be approximately 60% higher than the tension case.     

Interface fracture property of PEO ceramic coatings on aluminum alloy

This paper combines the four-point bending test, SEM and finite element method to study the interface fracture property of PEO coatings on aluminum alloy. The interface failure mode of the coating on the compression side is revealed. The ceramic coating crack firstly along the 45° to the interface, then the micro crack in the coating deduces the interface crack. The plastic deformation observed by SEM shows excellent adhesion property between the coating and substrate. The plastic deformation in the substrate is due to the interfacial crack extension, so the interface crack mode of PEO coatings is ductile crack. The results of FEM show that the compression strength is about 600 MPa.     

钛/铝/钛三层板的一次爆炸复合制备及界面结合性能评价

为评价一次爆炸复合工艺制备的钛/铝/钛三层复合板的界面结合性能,利用SEM、EDS对钛/铝/钛复合板的双层界面组织形貌以及界面元素分布进行了表征;对钛/铝/钛三层复合板进行了拉伸实验和弯曲变形实验。研究结果表明：复合板界面主要由波状界面和平直状界面构成;铝元素与钛元素在界面上发生了互扩散;拉伸和弯曲变形结果表明,一次爆炸复合工艺制备的钛/铝/钛三层复合板具有较大的抗拉强度和优良的界面结合性能,可以承受后续较大的二次塑性变形。     

TA32钛合金板成形性能与电磁辅助弯曲成形实验研究

由于TA32钛合金板室温成形性差、精度难以保证,开展了电磁辅助弯曲成形方法的实验研究,通过拉伸和电磁成形实验探究了TA32钛合金的力学性能和成形性能,获得了TA32钛合金板在准静态和动态拉伸下的应力、应变关系,给出了在电磁成形状态下的成形极限应变,阐明了电磁成形作用下的TA32钛合金的增塑机制。采用匀压式电磁辅助弯曲成形的方法对TA32钛合金板开展实验研究,结果表明:电磁辅助弯曲成形方法能够有效地提高弯曲件的成形精度,并且在一定条件下,放电能量越高,贴模效果越好、成形精度越高。带压紧翼的弯曲件的变形区外层过度伸长而产生减薄并开裂,不带压紧翼的弯曲件通过合理地控制放电电压能够获得较好的成形效果。