疲劳试验机的横梁锁紧

拉压疲劳试验机立柱与横梁间采用预应力锁紧套锁紧代替横梁的液压锁紧，能够大大改善拉压疲劳试验机上下夹头同轴度，有助于提高材料疲劳试验结果的正确性。     

超大型试验舱舱门锁紧件优化设计

试验舱在航空、航天、材料等领域具有广泛的应用,由于试验舱设备较大,需要采用大型液压锁紧机构来开关舱门。本文根据理论计算和实际工况的需求,设计了舱门的液压锁紧机构,结合使用情况,校核了锁紧件的接触强度;然后应用solidworks的有限元分析模块,采用逐步迭代的方法,优化了锁紧件的过渡圆弧R,锁紧接触厚度B,以及吊耳厚度B1的尺寸。通过上述优化设计,在保证锁紧件屈服安全系数和接触安全系数为1.4的情况下,与优化前相比,锁紧件的质量减少了38%。     

形状记忆聚合物材料及其在航天器新型锁紧释放机构中的应用

综述了形状记忆聚合物的种类、驱动方式以及形状记忆聚合物复合材料,同时介绍了其在空间锁紧释放机构中的应用,分析了各种锁紧释放机构的优缺点,并讨论了基于形状记忆聚合物材料的航天器新型锁紧释放机构关键技术,包括结构设计、加热源、承载能力、地面试验技术和重复使用性等。随着智能材料的进一步发展,基于形状记忆聚合物材料的锁紧释放机构有望取代火工品锁紧释放机构。     

螺纹锁紧环换热器结构分析

本文介绍了螺纹锁紧环型换热器的工作原理和结构特点,为螺纹锁紧环型换热器的设计积累经验。     

压力容器快开门安全锁紧装置的设计

压力容器上使用快开门装置越来越普遍,如何使压力容器快开门关闭和压紧后,能自动锁紧且安全可靠,一直是一项技术难题.提出一种新的纯机械控制压力容器快开门安全锁紧装置,由压紧钩、连杆、摇杆、机架及锁紧气缸组成,其中压紧钩、连杆、摇杆和机架构成了四杆机构.在容器门盖快速关闭和压紧后,利用四杆机构中的连杆和摇杆“死点”位置来锁紧,“死点”位置再由锁紧气缸锁定.该装置是借助压紧时本身的能源来实现锁紧的,压紧钩与压紧块既可压紧又能锁紧,不仅结构简单、操作方便,而且锁紧性能稳定、可靠.     

基于ADAMS的捆扎机锁紧机构的优化设计

气动捆扎机在使用过程中,存在锁紧力不足、锁扣不紧的问题.以锁紧机构为研究对象,通过理论计算分析影响锁紧力的因素,在ADAMS软件中对锁紧机构各主要杆件进行参数化,创建锁紧机构的虚拟样机优化模型;以锁紧力最大为目标,对模型各设计变量进行分析,找出了对目标影响最大的变量,通过优化确定模型的最佳结构;最后将导入钢扣柔性体导入虚拟样机模型,比较优化前后的锁紧机的性能.通过优化后锁紧机的锁紧力得到显著提高,其它性能也得到了改善.     

自卸汽车后板锁紧机构剖析

自卸汽车是指通过液压或机械举升而自行卸载货物的车辆。由于车厢需要倾翻一定角度卸料,车厢后板通过顶端两侧转动臂绕销轴能自动打开。运输过程中,车厢后板下部需要锁紧机构将后板与厢体锁紧成一体,防止货物抛洒,倾泻货物时,锁紧机构需安全打开,后板及时开启卸料,防止车辆倾翻,后板锁紧机构的安全有效尤为重要。该文介绍了几种自卸汽车后板锁紧机构的结构形式及特点,为自卸车设计提供参考,减少设计中问题的发生,提高了自卸车车厢后板启闭的安全性、方便性、实用性,可大大减少使用维修费,降低安全隐患。     

一种铁塑共用自攻锁紧螺钉的设计

自攻锁紧螺钉采用前端为三角截面后端为原截面的变截面螺纹结构的特殊自攻锁紧螺钉,具有能采用相同锁紧扭矩的作用下,锁紧材质为铁或塑料的特点,提高产线装配效率及降低了采购及库存管理成本。     

星载重叠天线锁紧座滑移故障分析

锁紧座在使用过程中常常会因振动发生接触面滑移故障,导致锁紧座锁紧状态失效。针对此问题,提出了一套锁紧座接触面力学状态的试验分析方法;首先设计加工了重叠天线试验模型并进行振动试验,得到频响曲线和动态应变曲线;然后在锁紧座接触面引入弹簧组等效模型,建立了重叠天线整体有限元模型,并根据试验结果对有限元模型进行了修正。对比分析了锁紧座发生滑移故障前后的接触力状态,评估了滑移故障对于锁紧座性能的影响。     

SJ 20382《楔形锁紧装置规范》行业标准修订介绍

本文阐述了SJ 20382-2007《楔形锁紧装置规范》行业标准修订的必要性，系统地介绍了SJ 20382-2021修订的原则、适用范围，给出了相对于SJ 20382-2007的变化，论述了标准项目设置及技术指标确定的依据。     

Locking in the incompressible limit for the element‐free Galerkin method

Volumetric locking (locking in the incompressible limit) for linear elastic isotropic materials is studied in the context of the element‐free Galerkin method. The modal analysis developed here shows that the number of non‐physical locking modes is independent of the dilation parameter (support of the interpolation functions). Thus increasing the dilation parameter does not suppress locking. Nevertheless, an increase in the dilation parameter does reduce the energy associated with the non‐physical locking modes; thus, in part, it alleviates the locking phenomena. This is shown for linear and quadratic orders of consistency. Moreover, the biquadratic order of consistency, as in finite elements, improves the locking behaviour. Although more locking modes are present in the element‐free Galerkin method with quadratic consistency than with standard biquadratic finite elements. Finally, numerical examples are shown to validate the modal analysis. In particular, the conclusions of the modal analysis are also confirmed in an elastoplastic example. Copyright © 2001 John Wiley & Sons, Ltd.     

Machine locking of degenerated thin shell elements

The degenerated shell element is one of the most efficient elements for analysing shell structures. However, it is known to result in rather stiff models when used in thin element applications. The phenomena associated with this behaviour are known as locking phenomena. This paper analyses the machine locking mechanism developed in thin to very thin Lagrangian and serendipity elements. The machine related locking phenomenon is distinguished from the shear and membrane locking phenomena. A remedy for the pure machine locking problem is developed for the two elements. The proposed remedy is based on the technique of the modified transverse shear modulus. It is also extended to control shear locking. The proposed technique is shown to completely eliminate machine locking. Also, it is shown to effectively alleviate stiffening effects due to the presence of spurious shear strain.     

激光器自动锁频方法研究综述

介绍了激光自动锁频的意义与目的,阐述了实现激光自动锁频的算法和常用的光学频率参考,分析了不同算法和频率参考的区别和优劣,探讨了在自动领域下实现激光锁频需要解决的问题和方法,指出了有待加强的领域,提出了部分仍待解决的困难,得出了当前激光自动锁频领域的发展方向和改良趋势,为激光器自动锁频的后续研究提供了参考。     

A new axi-symmetric element for thin walled structures

A new axi-symmetric finite element for thin walled structures is presented in this work. It uses the solid-shell element’s concept with only a single element and multiple integration points along the thickness direction. The cross-section of the element is composed of four nodes with two degrees of freedom each. The proposed formulation overcomes many locking pathologies including transverse shear locking, Poisson’s locking and volumetric locking. For transverse shear locking, the formulation uses the selective reduced integration technique, for Poisson’s locking it uses the enhanced assumed strain (EAS) method with only one enhancing variable. The B-bar approach is used to eliminate the isochoric deformations in the hourglass field while the EAS method is used to alleviate the volumetric locking in the constant part of the deformation tensor. Several examples are shown to demonstrate the performance and accuracy of the proposed element with special focus on the numerical simulations for the beverage can industry.     

由一例真空自耗电弧炉保护跳闸事件谈辅助电极锁紧结构的演进与发展

从实际工作现场一例真空自耗电弧炉辅助电极锁紧结构气压过低造成保护跳闸事件, 思考气压保护的设计缘由, 从而系统地对电弧炉辅助电极锁紧结构的发展过程进行了详尽的说明, 并对在现有锁紧结构下的使用提出建议, 有助于对该电弧炉核心结构加深认识, 也有助于设计、使用人员更深刻的理解该部位结构演进的过程, 为今后的使用、设计或改造工作提供借鉴。     

Threaded Fastener Secondary Locking Requirements

Secondary locking features in threaded fasteners are in widespread use in machinery, structures, and systems. In this paper, the mechanism for loosening of threaded fasteners is explained qualitatively and defined quantitatively in terms of the self-loosening moment inherent to threaded fasteners and external load-induced loosening moments. Equations for loosening moments are defined. This paper provides analysis which quantifies the locking action required to prevent loosening due to the inherent self-loosening moment and external load loosening moments in threaded fastener joints. This paper provides the basis and method for engineers to properly design or specify secondary locking features in threaded fasteners to provide sufficient locking and prevent loosening. Requirements for secondary locking feature moments are developed in terms of loosening moments and factor of safety. Test data and calculations are provided to substantiate the requirements. Examples are provided for common secondary locking features including prevailing torque and adhesive.     

Statistical definition of locking bandwidth in an array of synchronised microwave oscillators

Arrays of N weakly coupled oscillators are considered in different configurations. The locking bandwidth for these arrays is defined statistically. Various factors affecting the locking bandwidth and the effect of the coupling network topology on locking bandwidth are studied by solving the dynamic equations of the array numerically. The analytical locking bandwidth for two configurations of arrays is computed and the results are compared with the numerical solution of dynamic equations.     

自注入锁定微腔克尔频梳的锁定态研究

当前自注入锁定频梳理论研究在不同参数对于自启动效果的影响的探究尚不完善,用于解释锁定机理的工作点理论与数值仿真的结果差异较大且无法很好地解释部分实验现象。本文利用包含微腔背散射效应的LLE（Lugiato?Lefever Equation）方程,构建了自启动克尔微梳模型,使用基于分步傅里叶算法的数值仿真并结合各参数的物理内涵,探究了模型关键参数对于频梳自启动锁定态的影响;在此基础上,针对现有自注入锁定微腔频梳锁定理论不足的问题,从模型基本公式出发,修正了工作点锁定理论,提升了对自启动数值仿真中锁定态预测的准确性,提高了理论预测与数值仿真和实验结果的契合度。     

A variational method to avoid locking—independent of the discretization scheme

We present a variational method for problems in solid and structural mechanics that is designed to be intrinsically free from locking when using equal‐order interpolation for all involved fields. The specific feature of the formulation is that it avoids all geometrical locking effects (as opposed to material locking effects, for instance Poisson locking) for any type of structural or solid model, independent of the underlying discretization scheme. The possibility of employing equal‐order interpolation for all involved fields circumvents the task of finding particular function spaces to remove locking and avoid artificial stress oscillations. This is particularly attractive, for instance, for isogeometric analysis using unstructured meshes or T‐splines. Comprehensive numerical tests underline the promising behavior of the proposed method for geometrically linear and nonlinear problems in terms of displacements and stress resultants using standard finite elements, isogeometric finite elements, and a meshless method.