Design and Modeling on Stranded Wires Helical Springs

A stranded wires helical spring is formed of a multilayer and coaxial strand of several wires twisted together with the same direction of spiral. Compared with the conventional single wire spring, the stranded wires helical spring has the notable predominance in strength, damping and vibration reduction, which is usually used in aircraft engines, automatic weapons, etc. However, due to its complicated structure, the precise computation of its strength and rigidity need be a correct mathematical model, which then will be imported to finite element analysis software for solutions. Equations on solving geometric parameters, such as external diameters of strands and screw pitches of wires, are put forward in the paper. It also proposes a novel methodology on solving geometric parameters and establishing entity models of the stranded wires helical spring, which provides foundation of computing mechanical parameters by FEA. Then mathematical models on the centre line of the strand and the surface curve of each wire, after closing two ends in a spring, are proposed. Finally, geometric parameters are solved in a case study, and a 3D entity model of a spring with 3 layers and 16 wires is established, which has validated the accuracy of the proposed methodology and the 3D entity mathematical model. The method provides a new way to design stranded wire helical spring.

Three-stage Method for Identifying the Dynamic Model Parameters of Stranded Wire Helical Springs

The dynamic behavior of the stranded wire helical spring is described by a modified Bouc-Wen model while the model parameters must be identified using an identification method and experimental data. Existing identification methods usually relies either solely nonlinear iterative algorithms or manually trial and error. Therefore, the identification process can be rather time consuming and effort taking. As a result, these methods are not ideal for engineering applications. To come up with a more practical method, a three-stage identification method is proposed. Periodic loading and identification simulations are carried out to verify the effectiveness of the proposed method. Noises are added to the simulated data to test the performance of the proposed method when dealing with noise contaminated data. The simulation results indicate that the proposed method is able to give satisfying results when the noise levels are set to be 0.01, 0.03, 0.05 and 0.07. In addition, the proposed method is also applied to experimental data and compared with an existing method. The experimental data is acquired through a periodic loading test. The experiment results suggest that the proposed method features better accuracy compared with the existing method. An effective approach is proposed for identifying the model parameters of the stranded wire helical spring.

Present situation and countermeasure of low-alloy spring steel wire rod for domestic automobile

The variety,inner quality and surface quality of low-alloy spring steel wire rod for domestic automobile is summarized in detail.And according to commercial low-alloy spring steel wire rod variety, product quality level and its actual application situation on automobile supplied by present industrially developed country metallurgy enterprises,it is pointed that the variety of low-alloy spring steel wire rod for domestic automobile can't satisfy the requirements of automobile industry development,compare with overseas advanced technology,product quality has the following gaps:the first is that steel purity is low,the control level of non-metallic inclusions is not steady,there is often large grain difficult deforming non-deformation inclusions existing,the control level of steel purity has big difference,the level of large steel factory is high,but its steady has a large gap compare with foreign advanced level,not to mention small steel factory which research and development powder is low.The second is surface complete decarburization can' t be avoided completely.The third is that surface defects are more.The fourth is that composition segregation and structure segregation are not steady,steel wire can't be drawn normally when the segregation is serious. In all,the segregation of 55SiCrA is superior to 60Si2MnA obviously.The industrialization of domestic high level low-alloy spring steel wire rod can't seek quick success and instant benefits,independent innovation perseveringly must be adopted,the success may be reached after master core technologies and adopt the science way of step by step.

金属橡胶复合隔振器的动静态性能

设计一种对称式金属橡胶与线弹簧复合的隔振器,基于整体隔振,考虑安装板的柔性因素,建立相应的等效线性动力学模型.通过准静态力学试验,分析线弹簧刚度、金属橡胶密度和加载位移对金属橡胶复合隔振器准静态性能的影响.同时,进行随机振动试验,研究金属橡胶复合隔振器在整体隔振中的隔振性能.试验结果表明,复合样件的刚度特性趋向于线性效果.金属橡胶复合隔振器在谐振点处的峰值衰减是线弹簧隔振器的5倍以上,且系统的随机振动响应在频段0.12~2.00 kHz内都有较大程度的衰减.

65Si2CrV汽车尾门弹簧钢丝表面龟裂原因分析

3.90 mm 65Si2CrV汽车尾门弹簧钢丝生产过程中出现表面龟裂。对表面龟裂产生的主要原因进行分析,6.50 mm钢丝剥皮过程中表面产生厚度约3~4μm白亮层,在韧化转变不充分时遗传下来,后续拉拔时在钢丝表面重新生成白亮层,形成微裂纹,随着拉拔道次增加,表面白亮层厚度和裂纹深度不断增大,形成裂纹。通过调整剥皮钢丝的韧化工艺,在原韧化温度基础上提高50℃处理后,钢丝表面龟裂未再发生。

淬回火弹簧钢丝抗拉强度影响因素分析

弹簧钢丝淬回火后影响抗拉强度的因素较多。化学成分和显微组织对弹簧钢丝淬回火后的抗拉强度均有影响;表面全脱碳会降低弹簧钢丝淬回火后的抗拉强度;较快的加热速度和较高的线温有利于弹簧钢丝淬回火后获得较高的抗拉强度;同一条件下,不同淬火介质对弹簧钢丝淬回火后抗拉强度的影响不同;加大淬火系统的循环冷却能力可适当提高弹簧钢丝淬回火后的抗拉强度;热电偶的插入深度和回火温度的变化会直接影响弹簧钢丝淬回火后的抗拉强度。

汽车用65SiCrV6弹簧钢丝表面处理工艺改进

汽车用65SiCrV6弹簧钢丝拉拔时出现严重横向裂纹缺陷。利用体视显微镜、扫描电镜及能谱等手段对钢丝表面横向裂纹缺陷形成的原因进行分析,发现在横向裂纹缺陷附近的钢丝表面存在残留的氧化铁皮。对生产工艺流程和相关工艺参数进行改进,由原来的间歇式酸洗磷化改为在线酸洗磷化;充分利用正火余温并实施两道酸洗;使用酸性草酸表调剂并调整酸洗与磷化工艺参数。改进后的钢丝表面氧化层酸洗干净、磷化均匀,钢丝表面质量能满足拉拔工序使用要求。

10kV接地线防折断保护装置

为提升10 kV接地线连接处的耐用度、防止断股和磨损带来的安全风险,文章提出一种10 kV接地线防折断保护装置,防止接地线在收拾安置时因绕线角度过大,连接线耳的铜线受到过度扭曲,降低机械性能。此10 kV接地线防折断保护装置在使用过程中,能减少弯曲角度,并有效且可靠地固定在安装位置,从而进一步提供绝缘性能。

Dynamic behavior of bridge-erecting machine subjected to moving mass suspended by wire ropes

The dynamic behavior of a bridge-erecting machine, carrying a moving mass suspended by a wire rope, is investigated. The bridge-erecting machine is modelled by a simply supported uniform beam, and a massless equivalent ＂spring-damper＂ system with an effective spring constant and an effective damping coefficient is used to model the moving mass suspended by the wire rope. The suddenly applied load is represented by a unitary Dirac Delta function. With the expansion method, a simple closed-form solution for the equation of motion with the replaced spring-damper-mass system is formulated. The characters of the rope are included in the derivation of the differential equation of motion for the system. The numerical examples show that the effects of the damping coefficient and the spring constant of the rope on the deflection have significant variations with the loading frequency. The effects of the damping coefficient and the spring constant under different beam lengths are also examined. The obtained results validate the presented approach, and provide significant references in the design process of bridgeerecting machines.

基于滑轮组和永磁弹簧的变刚度关节设计与控制

基于永磁弹簧、滑轮组和类行星轮系结构提出了一种新型的绳索驱动变刚度机器人肘关节。阐述了关节中应用的原理和样机整体结构设计。利用模型间静力学关系和雅可比矩阵推导得到关节的刚度模型,并给出了关节刚度随磁弹簧刚度和关节位置变化规律。以变刚度关节的动力学模型为基础,设计了变刚度肘关节的刚度与位置解耦控制器。通过变刚度关节的刚度和位置解耦验证实验,验证了解耦控制器的准确性。通过轨迹跟踪实验,给出了关节刚度变化对关节位置控制的影响规律。本文提出的绳驱变刚度肘关节具有更轻的质量与结构,较好的刚度变化性能与运动精度。

60Si2MnA钢弹簧疲劳断裂原因分析

采用直径为4 mm、经油淬和回火的盘条制作的60Si2MnA钢弹簧,在疲劳试验早期断裂。检测了盘条的化学成分和拉伸性能,并对断裂的弹簧进行了断口分析和金相检验。结果表明:盘条的化学成分和拉伸性能均符合要求,但弹簧表面有细微裂纹、机械损伤和脱碳层等缺陷以及马氏体,导致疲劳性能降低从而在疲劳试验时过早断裂。

Recovery stress characteristics of TiNi alloy wires after partial martensitic transformation under different constraint conditions

The recovery stress characteristics of a TiNi shape memory alloy wire under different constraint conditions were studied. The results show that the recovery stress rate (dσ/dT) in the second heating cycle increases significantly with the increasing constraining-spring coefficient in the first heating cycle. As a result, a distinct discontinuity appears on the recovery stress curves of the TiNi alloy wires in the second heating process. Also, the results of differential scanning calorimeter(DSC) measurements show that after the thermomechanical process, the heating curve of the TiNi alloy wire consists of two independent endothermic peaks.

线簧丝倾角对线簧孔式电连接器贮存寿命的影响研究

线簧丝倾角是线簧孔式电连接器的重要设计参数之一,对其贮存寿命有显著影响。针对该问题,分析了贮存环境下线簧丝倾角改变时线簧孔式电连接器的失效机理,并建立了其贮存可靠性统计模型。在此基础上,建立了线簧孔式电连接器贮存寿命随线簧丝倾角变化的数学模型。最后,制定了恒定应力加速退化试验方案并开展相关试验,通过统计分析试验数据得到不同线簧丝倾角(7°~10°)下线簧孔式电连接器的性能退化模型参数估计值,实现了电连接器的贮存可靠性评估。结果表明,通过最小二乘法拟合得到的贮存寿命与线簧丝倾角的函数关系式的拟合优度高达0.9681,验证了所构建模型的准确性。研究结果可为后续线簧孔式电连接器的可靠性增长设计提供一定的理论基础和参考。

国产弹簧钢丝热处理生产线现状及发展方向

介绍了国产弹簧钢丝热处理生产线的现状和发展。目前国产弹簧钢丝生产线大多采用油淬火回火工艺,钢丝直径大于8 mm时,设计产能1 t/h。“高速”弹簧钢丝生产线采用“水淬火”工艺,对于直径大于8 mm的钢丝,生产线设计产能2.5 t/h。以直径10 mm 55SiCr弹簧钢丝为例,对热处理后钢丝性能和金相组织进行了分析。对未来弹簧钢丝生产线的设计理念进行了展望。

感应加热回火在中细规格钢丝生产中的应用

决定中细规格感应加热回火钢丝生产线稳定性的因素主要有收放线系统的车速稳定性及感应加热电源的加热方式和控制系统。目前Φ5.0 mm以上的弹簧钢丝采用感应加热方式实现了无铅化生产,而Ф5.0 mm以下的中细规格钢丝感应加热应用较少。设计感应加热回火生产线,采用单丝单控感应加热电源,严格控制收放线系统钢丝速度波动,可以满足中细规格油淬火钢丝的生产需求,同盘钢丝抗拉强度散差控制在50 MPa以内。

时效温度对GH4282合金弹簧丝材组织和性能的影响

为研制耐温900℃的高温合金弹簧,以固溶态的GH4282合金丝材为对象,研究了一次时效温度990~1030℃和二次时效温度788~950℃对组织和性能的影响。采用光学显微镜、高分辨场发射扫描电镜及能谱仪观察丝材微观组织、析出相形貌并分析其成分;采用MTS试验机测试丝材室温和900℃的拉伸性能。结果表明,990~1030℃一次时效+788℃二次时效处理后,GH4282合金丝材室温抗拉强度分别为1092、1085和1078 MPa,伸长率分别为34%、33%和35%;788和850℃二次时效处理后GH4282合金丝材室温抗拉强度分别为1085和1040 MPa,高温抗拉强度分别为460和467 MPa;当时效温度升高到950℃时,室温和900℃抗拉强度分别降低到846和303 MPa。二次时效温度由788℃升高到900℃时,小γ′相尺寸由20 nm增大到约100 nm,大γ′相尺寸由100 nm增大到约300 nm;温度继续升高到950℃时,小γ′相完全回溶,大γ′相数量明显减少。

冷绕成形螺旋弹簧回弹理论及数值模拟

针对现有研究未考虑张力对螺旋弹簧成形及回弹影响的问题,建立受张力影响的螺旋弹簧成形及回弹理论;讨论当簧丝受弯矩和张力共同作用时,弯矩与簧丝横截面应力、张力与簧丝横截面应力、回弹比与张力的关系;通过大型非线性有限元分析软件ABAQUS 6.8实现不同张力下螺旋弹簧冷绕成形过程的数值模拟。理论计算与模拟结果均表明:张力不同会导致弹簧最终回弹量的不同;张力越大,簧丝在卸载时越容易保持成形时的形状,回弹量越小;实际生产弹簧时,在除张力外的其他参数不易改变的情况下,可通过增大或减小张力的方法来减小或增大回弹量。

金属橡胶材料的理论模型研究

金属橡胶因此类金属构件具有类似橡胶的弹性而得名。本文从金属橡胶的成型工艺特点出发,以弹簧理论为基础,通过建立金属橡胶材料的力学模型,对材料的刚度特性进行理论分析,给出了金属橡胶材料的本构关系,为开发金属橡胶材料的产品设计与应用提供理论依据。

变刚度柔性机器人关节的设计与解耦控制方法

设计一种采用永磁变刚度装置的绳索驱动式柔性机器人关节,在不增加驱动力的情况下,增加关节刚度调整范围。详细阐述关节的机械结构和变刚度原理。利用雅可比矩阵和模型间静力学关系,得到关节刚度,位置和绳索伸长量的对应关系,实现了刚度与位置解耦。建立变刚度关节的动力学模型,以轨迹控制为目标,设计解耦控制器,搭建实验系统,验证本方案的可行性。采用永磁弹簧,绳索驱动的柔性关节可以有效的减小关节的质量,惯性和体积,同时具有较大的刚度调整范围以及较短的调整时间,较快的响应速度和较小超调量。此柔性关节的构型和控制方式也适用于多自由度柔性并联机器人关节的构建。

螺旋线圈强化管内单相流体传热的研究

研究了内插螺旋线圈的水平圆管内水的对流强化传热及流阻特性 ,探索了螺旋丝径不变 ,螺距变化对传热及流体阻力的影响 ;螺距不变 ,螺旋丝径变化对传热及流体阻力的影响。实验采用2 5mm× 2mm的紫铜圆管 ,实验段长 1 .68m ,管内走水 ,Re数的范围在 30 0 0～ 2 5 0 0 0之间。通过对实验数据的多元线性回归 ,得到了传热与流体阻力的实验关联式 ,采用 (Nus/Nu) 3.5/ ( fs/ f)作为评估传热与流阻性能的综合判据 ,实验结果表明 :在实验范围内 ,(Nus/Nu) 3.5/ ( fs/ f)的值在 1 .2～ 1 0 .7之间 ,大于 1 。