标准扭力扳手剪力寄生效应补偿方法研究

针对标准扭力扳手进行扭矩量传时因受到剪力干扰影响,导致扭矩测量准确度受到影响的特点,提出采用扭矩、剪力二分量传感器,通过补偿的方法抑制剪力对扭矩输出的干扰影响。实验结果表明:采用该方法可以显著提高标准扭力扳手的测量准确度。     

精密扭矩扳手的设计

本简述了应用扭力轴和杠杆、齿轮副放大的原理设计的一种精密扭力扳手。此扳手克服了一般扭力板手只能右旋及读数不准的缺点,能广泛用于测量螺纹紧固力矩大小，还可以做各种扭矩试验。     

基于多点弯曲应变测量原理的数字式扭力扳手研究

提出了基于多点弯曲应变测量扭矩的方法并通过力学分析进行了测量误差估计;在此基础上研制一种高精度数字扭力扳手并进行了实验验证。试验结果表明：研制的数字式扭力扳手,在试验力臂变动60％范围内测量误差可以控制在0.5％以内。     

确定扭力扳手偏差值的依据

我公司在引进联邦德国先进技术的同时,也引进了大批汽车装配工具——扭力扳手。由于我国至今没有扭力扳手计量检定规程,所以给扭力扳手的检测带来了无法可依的局面。我们认为,目前可参照国际标准ISO 6789进行检测。ISO 6789中规定: 扭力扳手最大扭矩值的偏差为±4％。扭力扳手最大扭矩值20％处偏差为±7％。扭力扳手被测值允许偏差和偏差值基本计     

扭矩测试仪和传感器的调试

随着工业技术的发展，力的概念发生了延伸，出现了扭矩这一物理量，并因此诞生了一大批专用工具和仪表，如扭力扳手、扭矩测试仪和扭矩传感器等。第一台偏转臂扭力扳手于70年前由wiltez Chrysles工程师发明，随后以此为基础，直至20世纪80年代推出了以微处理机编程为标志的先进的扭力测试仪期间，SR公司确立了在该领域中的领先地位，尤其应     

扭矩测试仪美国STURTEVANTRICMMONT公司

在上世纪 2 0年代末 ,ＷａｌｔｅｒＣｈｒｙｓｌｅｓ发明了世界上第一把偏转钢梁式扭力扳手 ,由于它第一次准确的测量出螺栓的装配扭矩而被汽车装配厂广泛的接受。从此以后斯图特迈·里奇蒙特公司成为世界上著名的扭矩工具和扭矩测试仪制造公司。斯图特迈·里奇蒙特公司不但生产各种定值、可调式、表盘指示式和电子扭矩扳手 ,而且还生产各种机械式和电子式扭矩扳手测试仪。在生产中使用的扭矩扳手测试仪 ,主要有手动加载和机械加载两种。其中经济型数字扭矩扳手测试仪 (图 1)是斯图特迈·里奇蒙特公司新开发的产品。这种扭矩扳手测试仪不但…     

扭矩测试仪

在上世纪20年代末,Walter Chrysles发明了世界上第一把偏转钢梁式扭力扳手,由于它第一次准确的测量出螺栓的装配扭矩而被汽车装配厂广泛的接受.从此以后斯图特迈·里奇蒙特公司成为世界上著名的扭矩工具和扭矩测试仪制造公司.     

扭力扳手的校验与调整

扭力扳手作为一种能测力矩的计量器具,必须经常校验,以保证示值符合紧固件的装配要求。本文介绍我厂对应用较广的 AC 型定扭矩扭力扳手的校验与调整。一、校验的理论依据按力矩     

扭矩扳手的简易校检法

扭矩扳手又称扭力扳手，是近几年来迅速发展并推广应用的一种计量工具，用于拧紧有扭矩要求的螺纹紧固件。其规格品种比较多，大致可分为铝壳式、棘轮式、电动式、表盘式（指针式）等。由于各种扭矩扳手样式和性能不同，因此各有特点，一般铝壳式和表盘式扭矩扳手由于实用、操作简单方便，因此应用比较广泛。其中铝壳式具有预置任意数值和发讯装置，当紧固件拧紧扭矩达到预置数值时能自动发出讯号，解除力后能自动复位以备再用。表盘式则通过盘上指针显示示值，使用简便，价格低廉，适用于小扭矩要求的地方。但示值误差较大。随着工业生产的…     

扭矩扳手示值误差调整方法及使用经验

扭矩扳手作为一种机械式扭力工具,经过一段时间使用或操作方法不当,容易造成示值误差超差或损坏.为延长扭矩扳手的使用寿命,操作人员应掌握正确的使用方法,定期进行维护保养,并周期送计量技术机构进行技术状态确认,同时计量工作人员应掌握必要的调整方法,对示值误差超差的应进行调整,尽量使损失降到最低.     

架盘扭力天平刻度盘示值误差及其校准方法

架盘扭力天平是由普通架盘天平改型的衡量仪器。由于没有相应的计量检定规程或校准规范,在校准其刻度盘示值误差时因方法不规范而存在诸多问题。本文作者根据多年从事计量检测工作的经验,对架盘扭力天平刻度盘示值误差的要求和校准方法提出了一些实用性建议。     

Torsion of carbon fiber composite pyramidal core sandwich plates

A combined theoretical, experimental and numerical investigation of carbon fiber composite pyramidal core sandwich plates subjected to torsion loading is conducted. Pyramidal core sandwich plates are made from carbon fiber composite material by a hot compression molding method. Based on the Classical Laminate Plate Theory and Shear Deformation Theory, the equivalent mechanical properties of laminated face-sheet are obtained; based on a homogenization concept combined with a mechanical of materials approach, the equivalent in-plane and out-of-plane shear moduli of pyramidal core are obtained. A torsion solution is derived with Prandtl stress function and can be used in the sandwich plate with orthotropic face-sheets and orthotropic core. The influences of material properties and geometrical parameters on the equivalent torsional stiffness are explored. In order to verify the accuracy of the analytical torsion solution, experimental tests of sandwich plate samples with different face-sheet thicknesses are conducted and two types of finite element models are developed. Good agreements among analytical predictions, finite element simulations and experimental evaluations are achieved, which prove the validity of the present derivation and simulation. The proposed method could also be applied in design applications and optimization of the pyramidal core sandwich structures.     

On the Determination of the Stress State of a Solid Cylinder in Tension with Torsion

The solution of problems on the determination of the stress state within the framework of flow theory with isotropic hardening has been obtained for a solid cylinder made of a material sensitive to the strain rate under conditions of proportional loading in tension combined with torsion. An analysis of the obtained expressions has been performed. The results of tensile tests with simultaneous torsion under conditions of superplasticity were used to plot a stress-strain diagram for titanium alloy VT9 with the use of the expressions for the stress intensity.     

Torsion of strain gradient bars

The governing differential equation and both classical and non-classical boundary conditions of strain gradient bars are derived using variational approach. A closed-form analytical solution is obtained for static torsion and the characteristic equation, which gives the natural frequencies, is derived and analytically solved for the free torsional vibrations of the strain gradient microbars. A fixed-fixed microbar is considered as a specific case to investigate the torsional size-dependent static and free-vibration behavior of strain gradient microbars. The results of the current model are compared to those of the modified couple stress and classical theories.     

扭矩加载装置标准不确定度

扭矩加载装置的不确定度随被测量对象而变化,通常参考实验数据或长期的测量经验来估计。通过对扭矩扳手的受力与误差原因分析,以B类方法来评定加载装置的标准不确定度,推导各种矢量作用下引入的标准不确定度的计算公式,将实验方法和经验方法改变为量化方法,所得到的相对不确定度与扭矩扳手有效力臂长度、传感器的长度、结构表面的粗糙度、转换接头有关。此量化结果与PTB的实验结果相吻合,对扭矩扳手检定仪的设计制造和用户选择设备具有参考意义。     

Torsion of a non-homogeneous infinite elastic cylinder slackened by a circular cut

We consider the torsional deformation of a non-homogeneous infinite elastic cylinder slackened by an external circular cut. The shear modulus of the material of the cylinder is assumed to vary with the radial coordinate by a power law. It is assumed that the lateral surface of the cylinder as well as the surface of the cut are free of stress. The main object of this study is to establish the effect of the non-homogeneity on the stress intensity factor at the tip of the cut. The problem leads to a pair of dual series relations, the solution of which is governed by a Fredholm integral equation of the second kind with a symmetric kernel. This equation is solved numerically by reducing it to an algebraic system. It is concluded that for any degree of non-homogeneity and for D, the relative depth of the cut, greater than 0.6, the cylinder may be replaced by a half-space. However, as the non-homogeneity increases, D decreases.     

正交各向异性厚壁圆筒扭转冲击的一种解法

本文利用特征函数的方法，得到了满足混合边界条件下正交各向异性厚壁圆筒在扭转冲击作用下的动态剪应力的解析表达式。在实例计算中，求解了正交各向异性厚壁圆筒在不同的扭转载荷作用下，两种厚壁结构的剪应力响应历程和分布规律。     

Numerical Analysis of Large Strain Simple Shear and Fixed-End Torsion of HCP Polycrystals

Large strain homogeneous simple shear of Hexagonal Close Packed (HCP) polycrystals is first studied numerically. The analyses are based on the classical Taylor model and the Visco-Plastic Self-Consistent (VPSC) model with various Self-Consistent Schemes (SCSs). In these polycrystal plasticity models, both slip and twinning contribute to plastic deformations. The simple shear results are then extended to the case of solid circular bars under large strain fixed-end torsion, where it is assumed that the solid bar has the same mechanical properties as the element analyzed for large strain simple shear. It is shown that the predicted second-order axial force is very sensitive to the initial texture, texture evolution and the constitutive models employed. Numerical results suggest that the torsion test can provide an effective means for assessing the adequacy of polycrystal plasticity models for HCP polycrystalline materials.     

Torsion of a finite cylinder by locally distributed friction forces

We study the stressed state of a finite cylinder under the action of torsional stresses caused by the action of friction forces. As a result of the separation of the angular variable, we reduce the analyzed three-dimensional problem to the solution of two-dimensional boundary value-problems. It is shown that the loads caused by pure torsion strongly affect the stressed state of the cylinder. The problem of pure torsion of a cylinder by loads locally distributed over its lateral surface is analyzed. It is shown that the singularities of stresses τ_φz at the point of discontinuity of the load are formed under the action of piecewise continuous tangential loads. Finally, we study the variations of the maximum shear stresses in the cylinder when the distribution of load approaches a rectangular distribution.     

Analysis of the torsional strength of hardened splined shafts

The current study presents a finite element modeling framework to determine the torsion strength of hardened splined shafts by taking into account the detailed geometry of the involute spline and the material gradation due to the hardness profile. The aim is to select a spline geometry and hardness depth that optimizes the static torsion strength. Six different spline geometries and seven different hardness profiles including non-hardened and through-hardened shafts have been considered. The results reveal that the torque causing yielding of induction hardened splined shafts is strongly dependent on the hardness depth and the geometry of the spline teeth. The results from the model agree well with experimental results found in the literature and reveal that an optimum hardness depth maximizing the torsional strength can be achieved if shafts are hardened to half their radius.