检定电子汽车衡时偏载调整方法浅析

当电子汽车衡作为贸易结算计量器具时．必须实行周期检定。按JJG555-1996检定规程．偏载检定是电子汽车衡周期检定项目中的一项必检项目。进行偏载检定时，如果误差超出允许范围则要进行偏载调整。由于1台汽车衡需要多个传感器。而每个传感器的输出灵敏度和输出电阻不可能完全一致．会使传感器单位输出阻抗的输出灵敏度不一致，这样必然存在偏载误差。另外由于安装原因造成传感器之间不平衡，也会产生偏载误差。对于分别采用模拟式传感器和数字式传感器(DLC表示)的两种类型汽车衡来说，偏载调整方法有所不同，下面仅对这两种类型汽车衡的偏载调整方法作一探讨。     

电子汽车衡偏载误差的调整方法

电子汽车衡作为贸易结算用计量器具．必须进行周期检定。偏载误差作为周期检定时的必检项目．如超出允许误差的范围，就必须进行偏载误差调整。 鉴于目前电子汽车衡基本采用并联工作方式．以下就并联工作方式的三种电子汽车衡偏载误差的调整方法进行分析。     

数字式电子汽车衡的偏载调整

本文对数字式电子汽车衡工作原理和偏载进行了浅析,阐述了偏载的自动和手动调整方法。     

模拟式电子汽车衡偏载调试浅析

电子汽车衡广泛应用于各工矿企业及公正计量等商贸活动中,电子汽车衡的准确是保证其正常使用的前提条件,偏载调试是检定汽车衡过程中的一个重要步骤,其调试准确程度直接影响到汽车衡的正常使用。本文以SCS-80型电子汽车衡为例,介绍多年检定工作总结出的偏载调试的方法。     

数字式汽车衡的偏载调整

本文对数字式汽车衡工作原理和偏载进行了浅析,阐述了偏载的几种调整方法。     

调整电子汽车衡偏载误差的简便方法

<正>电子汽车衡(以下简称"汽车衡")广泛用于工贸企业的大宗物料计量和贸易结算,其计量是否准确、可靠十分重要。影响汽车衡称量准确性的因素有很多,其中偏载误差(又称为"四角误差")是最常见的故障之一。因此,在汽车衡安装调试或检修时,对偏载误差进行调整,使之符合JJG555-1996《非自动秤通用》检定规程要求,     

电子汽车衡加载状态与检定结果研究

针对采用砝码法和衡器载荷测量仪法检定电子汽车衡的加载状态,结合实际尺寸和边界条件建立电子汽车衡结构模型;应用数学模型计算和有限元分析手段,对不同加载状态下承载器的变形特性以及对称重传感器的影响进行了分析。研究结果表明,两种方法在称重和偏载检定时结果略有差异,但不影响检定结果判断。通过实际称重和偏载检定测试,验证了理论分析结论。     

电子汽车衡偏载误差调整方法

下面以上海耀华称重系统有限公司的数字式仪表XK3190-DS3的数字式汽车衡为例,介绍采用XK3190-DS3数字称重显示器运用偏载调整软件进行偏载误差调整的方法。偏载误差调整方法程序结构图如图1所示。一、采用角差调整程序自动调整(全自动单点四角     

对JJG 539—2016《数字指示秤》检定规程的分析讨论

根据检定工作的实践,对JJG 539—2016规程中的偏载测试、重复性测试几个问题进行分析讨论,认为本规程仅适用于电子计价秤和电子台案秤以及最大秤量Max≤10t的电子秤的检定,但不适合检定电子汽车衡,尤其是目前普遍使用的大秤量汽车衡。     

韶钢电子汽车衡改造简介

位于韶钢烧结西路西边（以下简称“烧西”）的汽车衡原是一台采用模拟式称重传感器的60t电子汽车衡．因其长时间超负荷运行．造成该汽车衡上秤引道破损、秤体严重开裂,严重影响运行安全及计量性能．且无法满足韶钢产能扩大的需求。因数字式称重传感器电子汽车衡具有自动调整偏载误差．四角调整方便．自诊故障能力强,抗干扰能力强．杜绝作弊现象．防潮、防腐、防雷能力突出等模拟式汽车衡无法比拟的优势．故韶钢计控部将该60t模拟式汽车衡改造成150t数字式汽车衡。     

Analytical model for prediction of load capacity of RC columns confined with CFRP under uniaxial and biaxial eccentric loading

This paper presents an analytical model for prediction of the load carrying capacity of reinforced concrete (RC) columns confined with carbon fiber reinforced polymers (CFRP) under uniaxial and biaxial eccentric loading. The model is based on realistic material laws and accounts for the non-linear stress–strain behavior of both unconfined and CFRP-confined concrete. Under uniaxial eccentric loading, the column cross-section is discretized into finite layers along the section depth. For a symmetric square cross-section subjected to biaxial eccentric loading with equal eccentricity about each principal axis, the column cross-section is discretized into finite layers along the diagonal of the column cross-section. For a given strain distribution in a direction perpendicular to the neutral axis, the sectional forces are integrated numerically and the load capacity of the column is predicted using an iterative process. For rectangular and non-symmetric square cross-sections subjected to biaxial eccentric loading, the load capacities under uniaxial eccentric loading along each principal axis are first derived independently. The column load capacity under concentric axial loading is calculated. The determined distribution of the column load capacities under uniaxial eccentric loading and concentric loading are then utilized to compute the load capacity under biaxial eccentric loading using the reciprocal load equation. An experimental study was carried out to examine the effectiveness of the CFRP-confinement to improve the load capacity and ductility of RC columns under biaxial eccentric loading. The accuracy of the proposed analytical model was demonstrated by comparing the model predictions to results of the current experimental study in addition to experimental data published in the literature.     

重组竹柱偏心受压力学性能

为了研究偏心距对重组竹柱的偏心受压力学性能的影响, 对6根不同偏心距的重组竹柱进行了偏心受压试验。结果表明:在偏心载荷作用下, 试件破坏形态主要表现为柱身中部竹材纤维受拉断裂;随着相对偏心距的增大, 峰值载荷减小, 而对应峰值载荷时试件的竖向位移和中部截面侧向挠度增大, 弯曲变形越加显著, 对应峰值载荷时, 重组竹柱偏心受压试件的竹材压应变远远大于轴心受压试件, 前者是后者的3.1~4.6倍, 偏心受压重组竹柱的受压侧竹材的受压变形能力及强度得到了充分的发挥;基于试验结果与理论分析, 提出了重组竹柱偏心受压承载力计算方法, 平均绝对误差小于5%, 计算结果与试验结果一致。      

单轴对称十字型钢混凝土中长柱偏压性能试验研究

为研究单轴对称十字型钢混凝土中长柱偏心受压性能,进行8根单轴对称十字型钢混凝土中长柱偏压试验,分别研究不同加载方向十字型钢偏心率和荷载偏心率对试件破坏模式、侧向挠度、荷载-挠度曲线和极限承载力的影响规律,建立该组合柱正截面受压承载力计算方法。结果表明:根据荷载偏心率的不同,组合柱表现出小偏心受压破坏和大偏心受压破坏两种形态,组合柱截面应变符合平截面假定。正向偏心时,十字型钢偏心率增大,试件极限承载力和变形能力小幅降低;负向偏心时,十字型钢偏心率对发生小偏心受压破坏的试件偏压性能影响较小,发生大偏心受压破坏的试件极限承载力随十字型钢偏心率增加略有提高;荷载偏心率增大,试件初始刚度和极限承载力降低。将单轴对称十字型钢偏于安全地换算成H型钢,采用规范JGJ 138?2016计算换算截面试件偏压承载力,计算结果偏于保守,采用该文提出的方法计算的试件偏压承载力与试验值吻合较好。     

钢管混凝土偏心受压应力—应变试验研究

试验共对18根钢管混凝土偏心受压短柱进行了测试。试验参数包括偏心率和截面参数(含钢率和混凝土强度)。介绍了试件的内容、试验装置与方法,并重点进行了偏心率对钢管混凝土偏压构件受力性能影响的分析。分析结果表明,偏心率大,相同的纵向应变所对应的钢管环向应变小,紧箍力对提高混凝土强度的作用也随之削弱,构件的承载力也明显降低,达到极限承载力时钢管受压边缘的应变值也相应要大。但偏心率对构件的延性系数影响不大。     

偏心轴向荷载作用下薄壁箱梁的约束扭转翘曲应力研究

以薄壁箱梁的约束扭转分析理论为基础,将薄壁箱梁所受偏心轴向荷载作为一种外加双力矩荷载考虑,建立偏心轴向荷载作用下薄壁箱梁约束扭转的双力矩这一广义内力的计算公式。为了便于计算翘曲应力,进一步推导了扭转中心位置及主扇性坐标的实用计算公式。通过对一模型箱梁进行计算,并与按通用有限元软件ANSYS壳单元计算结果进行比较,验证了该文方法和所推导公式的正确性。详细分析箱室高宽比以及悬臂板宽度变化对偏心轴向荷载作用下薄壁箱梁约束扭转翘曲应力的影响。研究结果表明:箱室高宽比及悬臂板宽度对悬臂板端部翘曲应力的影响最大,对腹板与上翼缘、下翼缘交接处翘曲应力的影响相对较小;在偏心轴向分布荷载作用下,悬臂箱梁固定端横截面上控制点处的翘曲应力可达到初等梁应力的12%,不容忽视。     

粘弹性流体法向力作用下的抽油杆柱横向振动仿真

聚合物抽油机井抽油杆柱在粘弹性流体井筒内偏心运动时，抽油杆柱受到交变粘弹性流体法向力的作用。该文指出了交变粘弹性流体法向力是抽油杆柱横向振动的激励。考虑抽油杆柱所受粘弹性流体法向力与抽油杆柱横向振动位移的耦合关系，建立了受粘弹性流体法向力作用的抽油杆柱在油管内横向振动仿真的力学和数学模型。采用有限差分法和Newmark法实现了对抽油杆柱在油管内横向振动的仿真计算。分析了抽油杆柱在初始偏心和粘弹性流体法向力激励下的横向振动规律。仿真结果表明:抽油杆柱的任何初始偏心都会导致在全井范围内发生杆管碰撞现象；抽油杆柱下冲程杆管碰撞更为剧烈，且泵端附近碰撞力最大；由于粘弹性流体法向力的存在，杆柱与油管壁的接触碰撞更加频繁，加剧了杆管偏磨。所建立的粘弹性流体法向力作用下的抽油杆柱横向振动仿真模型对于聚驱井杆管偏磨分析、扶正器的优化配置具有指导作用。     

Flax and polyparaphenylene benzobisoxazole cementitious composites for the strengthening of masonry elements subjected to eccentric loading

To address the structural problems caused by eccentric loads in unreinforced masonry, three different types of masonry were prepared based on clay bricks bonded with a natural hydraulic lime mortar combined with a flax or polyparaphenylene benzobisoxazole (PBO) fabric-reinforced cementitious matrix (FRCM) composite. The mechanical behaviour when subjected to concentric and eccentric loads was studied by performing axial compression tests, with eccentric load tests only carried out in instances of large eccentricities. Analysis of the load–displacement and moment–curvature response revealed that both the flax- and PBO-based strengthening systems improve the strength and deformability of masonry. However, compared to the PBO fabric composite, the use of flax fabric provides a greater deformability that helps prevent the composite and substrate debonding.     

Behaviour of FRP wrapped normal strength concrete columns under eccentric loading

Eccentric loads are common for columns in buildings and other types of structures. Columns that are in the border of buildings, especially corner columns and columns near opening are usually subject to a combination of axial load and bending moment, thus creating an equivalent eccentric load. Fibre Reinforced Polymers have been used in strengthening/retrofitting columns and other types of elements. The results by and large are satisfactory. Most of the research studies undertaken in strengthening columns are based on concentrically loaded columns. In effect, the behaviour of FRP wrapped columns under the influence of eccentric loading is less known compared to concentrically loaded columns. This paper presents results of testing six normal strength concrete columns under eccentric loading. The columns are wrapped with different number of layers of FRP. Results show that wrapping a column with an adequate number of FRP layers will result in higher strength, ductility and energy absorption than a column reinforced with steel bars.     

Parametric study of the post-buckling strength of structural core sandwich panels

Post-buckling strength of simply supported orthotropic corrugated board panels subjected to edge compressive loading has been investigated using geometrically non-linear finite element analysis (FEA). Adjustments of the transverse shear stiffnesses in the FEA were necessary and performed by comparing the critical buckling load calculated by FEA with a closed form solution. The collapse load of the sandwich plate was calculated based on material failure of the facings predicted from Tsai-Wu failure theory. Parametric studies were performed to investigate the sensitivity of the collapse load to changes in the transverse shear stiffnesses of the core, initial out-of-plane imperfections, asymmetry in board construction, slenderness ratio and eccentric loading of the plate. It was found that a reduction of the transverse shear stiffnesses of the core below a certain limit produces a significant reduction in the collapse load. Panels are said to be insensitive to imperfections and this holds true when the imperfections are the same as or lesser than the thickness of the panel, but a 40% reduction of the collapse load is observed for imperfections that are ten times the panel thickness. From a design point of view it is shown that a symmetrical board is preferred because an asymmetric board as well as eccentric loading of the panel significantly reduce the collapse load. It is also shown that the critical buckling load is directly related to the slenderness ratio of the panel whereas the collapse load is not.     

考虑导线偏心覆冰对四分裂导线舞动的影响

采用风洞试验获得典型新月形覆冰四分裂导线的升力、阻力和扭矩系数随风攻角的变化规律。基于ABAQUS有限元软件提出一种考虑偏心覆冰作用的导线数值模拟方法,并利用算例验证了该方法的正确性。在此基础上,利用ABAQUS用户自定义子程序UEL编写气动载荷单元,实现考虑偏心覆冰作用的导线舞动数值模拟方法。采用该方法与传统数值模拟方法对典型新月形覆冰四分裂导线的舞动特征进行对比分析。结果表明,该方法能准确反映覆冰导线运动过程的扭转特性。考虑偏心覆冰作用后,覆冰四分裂导线的位移和扭转角幅值明显增大,振动形态更为复杂。因此,在研究覆冰导线舞动时,有必要考虑偏心覆冰作用的影响。