Testing steel-cord belt splices with a magnetic conveyor belt monitor

Steel-cord belt splices fail for a variety of reasons, including corrosion, poor vulcanising, and incorrect construction. The latter often leads to early failure. A conveyor belt monitor (CBM) has been used to evaluate the splice lay-up. The mass of the overlapping cords and their magnetic signature are used to rapidly locate suspect splices in the belt. The general shape of the magnetic signature for ideal splices will be discussed.     

Encapsulation of a pressure sensitive adhesive by spray-cooling: Optimum formulation and processing conditions

An industrial pressure sensitive adhesive (PSA) was encapsulated by spray-cooling using hydrogenated palm oil. A screening design methodology was used to evaluate the impact of some formulation and process variables on the particle properties. Six operating factors were retained and the results considered were the production yield, the particle volume-surface average diameter D₃₂, the residual humidity, the ratio of the fusion enthalpies of the polymorphs α and β′/β and the normalized peeling force. The statistical analysis of the results showed a negligible impact of the parameters related to the process. The heating temperature, the PSA and surfactant ratios were the most significant factors. It was possible to produce spherical particles with a mean size of 17.7 μm and a normalized peeling force of 0.218 N m²/g. The production yield was 70%. A duplicate test confirmed the results. Mechanical tests on unitary particles showed an increase of the rupture and adhesion forces with particle size.     

Optimum design for the sensing device in a conveyor balance

Measurement Techniques -     

注塑工艺和老化条件对组合件粘接强度的影响

为提高聚苯硫醚-不锈钢纳米成型技术组合件的粘接强度,研究了注塑成型参数和老化条件对粘接强度的影响,主要考察了金属表面温度、塑料熔融温度、注射速度以及保压压力4个参数,采用正交分析法评估了各参数对粘接强度的影响程度,通过497 h的老化实验研究了不同老化条件(-20、23、90、130℃)与粘接强度保持性之间的关系.结果表明:金属表面温度对粘接强度有最大的正面影响,而注射速度的影响最小;在-20、23、90、130℃温度下的粘接强度分别保持了初始值的96.52%、102.86%、106.21%、110.83%,组合件的粘接强度总体没有明显降低,说明得到的聚苯硫醚-不锈钢组合件具有较好的耐老化性能.     

Optimum laminate design for strength and stiffness

A method is presented for minimum weight optimum design of symmetric fibre-composite laminates subject to multiple in-plane loading conditions which takes into account membrane stiffness requirements and strength limitations. The problem is cast as a non-linear mathematical programming problem in which the thicknesses of material placed at preassigned orientation angles are treated as the only design variables. The non-linear programming formulation is transformed into a sequence of linear programs employing an adaptation of the method of inscribed hyperspheres in which only critical and near critical constraints are considered at each stage in the procedure. Example applications illustrate that the method presented offers an efficient and practical optimum design procedure for the fundamental and recurring problem treated.     

平面转弯带式输送机启动过程计算机仿真

针对大型平面转弯带式输送机动态设计问题,通过平面转弯带式输送机转弯部分的导向力和阻力分析,得出转弯段输送带运行的阻力计算方法,采用离散模型建立了系统的动力学方程。开发了平面转弯带式输送机动态分析软件,通过对实际系统的仿真,得出输送机启动过程各单元的位移、速度、加速度和张力等数值结果,绘制出相应的曲线,证明了其正确性。通过对直线运行输送机和转弯运行输送机仿真结果的比较,得出了转弯运行对带式输送机的影响。     

Designing a belt conveyor controller in a bottling plant using fuzzy logic and genetic algorithms

This paper presents an industrial case study relevant to a fuzzy logic controller designed via a properly developed genetic algorithm. We consider an example of a fuzzy logic‐based industrial process‐controller. In particular, we deal with the problem of controlling the speed of a belt conveyor for glass containers in a bottling plant. The primary objective of the controller is to guarantee the continuous feed to the filling station, in the presence of frequent gaps between bottles. The secondary objective is to reduce the impact speed between arriving bottles and those standing in the queue, in order to reduce the plant noise. High‐performance parameters of the fuzzy controller are found by a properly developed genetic algorithm. The results provided by Monte Carlo simulations demonstrate that, with such controllers, it is possible to achieve both the objectives mentioned above. Copyright © 2001 John Wiley & Sons, Ltd.     

带式输送机功率计算方法及其工程应用问题的研究

 通过CEMA带式输送机功率和张力计算方法与德国标准DIN22101计算方法的比较分析,明确了CEMA方法的特点,以Visual Basic 6.0为开发工具开发了CEMA计算方法的带式输送机功率张力计算软件,通过实例和工程应用验证了软件的正确性．通过研究CEMA算法中弯曲阻力系数 K_y 和DIN22101标准中模拟摩擦系数 f 的关系,得出CEMA算法主要阻力的规律;给出了设定模拟摩擦系数修正功能,采用温度校正系数的修正技巧使软件能够按输入的模拟摩擦系数进行功率和张力计算,扩展了软件的功能．针对应用DIN22101标准时没有与温度相关的修正方法,利用CEMA算法得出模拟摩擦系数在低温情况下的修正值．     

A control theoretical modelling for velocity tuning of the conveyor belt in a dynamic mixed-model assembly line

This paper proposes a control theoretical modelling to study dynamic behaviour of a mixed-model assembly line. First, an open-loop model is developed for the system, then examined via different conveyor’s velocity values. It is realised that the performance of the system is very sensitive to the velocity; therefore, a closed-loop (CL) model is developed taking feedback from the system. By the use of proportional-integral-derivative (PID) controller and SIMULINK, some interesting results are obtained applying CL model: regardless of the sequence of the products in the line, the total work-overload and idleness always equals to zero. Moreover, less working area within the workstation is required. Based on the statistical analysis, it is found that no significant increase in makespan is imposed by CL model. It is also shown that PID controller is robust not only to the disturbances of the velocity, also to the uncertainties in the assembly operation times. These results are supported by many numerical experiments dealing with different test problems, line configurations and sequences. Finally, using a discrete event simulation model, the proposed approach is applied into a seru production mode. Simulation results show that the feedback PID controller can deal with real-world assembly line problems, successfully.     

Fatigue strength of woven fabric composites with drilled and moulded-in holes

The fatigue strength of glass-fiber woven-roving composites with a circular hole has been examined. Circular holes of two types, drilled and moulded-in, were considered. Experiments on the fatigue life and damage processes in (0, 90)_s and (45, −45)_s woven-roving composites with hole diameters of 5, 10, 14 and 19 mm were conducted. Experimental results show that laminates with moulded-in circular holes exhibit higher fatigue strength than those with drilled holes as a consequence of the altered mode of failure. Photographs of fatigue failure processes and specimen elongation with life are presented. The failure phenomena of laminates with drilled and moulded-in holes are compared and discussed.     

Compressive strength,abrasion resistance and energy absorption capacity of rubberized concretes with and without slag

It has been estimated that around one billion tires are withdrawn from use in the world every year. Therefore, the development of new techniques for recycling waste tires is necessary. A number of innovative solutions that meet the challenge of the tire disposal problem involve using waste as an additive to cement-based materials. In this study, an experimental program was carried out to determine the compressive strength, abrasion resistance, and energy absorption capacity of rubberized concretes with and without ground granulated blast furnace slag (GGBFS). For this purpose, a water–binder ratio (0.4), four designated levels of crumb rubber (CR) contents (0, 5, 15 and 25% by fine aggregate volume), and three levels of GGBFS content (0, 20, and 40%) were considered as experimental parameters. In total, 12 concrete mixtures were cast and tested for compressive strength, abrasion resistance, and energy absorption capacity. Test results indicate that using CR aggregate decreases compressive strength and abrasion resistance of the concretes, but increases energy absorption capacity significantly.     

Micromechanical modeling approaches for the stiffness and strength of knitted fabric composites: a review and comparative study

Knitted fabric reinforced composites have been investigated widely in recent years. A number of different micromechanical modeling schemes have been proposed in the published literature for various types of knitted fabric composites. However, to date, no comparative study has been made to evaluate the suitability of different modeling schemes to predict the stiffness and strength properties of knitted fabric composites. This paper presents a review of currently developed micromechanical modeling techniques for predicting the stiffness and strength of knitted fabric composites. Further, a comparative study of the predictive capabilities of various techniques is carried out based on a plain weft knitted glass fiber fabric reinforced epoxy matrix composite. Useful conclusions are drawn based on the comparative study.     

An investigation of the strength and tightness of joints based on a modified adhesive

The results are given of an investigation of the strength and tightness of joints in bar specimens and shells of silicate materials based on a modified epoxy adhesive. The promise of use of the studied adhesive for assembly of shells of silicate materials operating in contact with sea water is shown.Institute of Problems of Strength, Academy of Sciences of the Ukrainian SSR, Kiev. Leningrad. Translated from Problemy Prochnosti, No. 9, pp. 79–83, September, 1989.     

基于粒子群算法的高黏度大比重物料无轴螺旋输送机构优化设计

 为解决高黏度大比重物料无轴螺旋输送机的螺旋叶片变形问题,利用粒子群优化算法,以无轴螺旋叶片刚度变形最小为优化设计目标,构建了基于粒子群算法的无轴螺旋叶片优化设计模型.应用构建的理论模型,进行了实例设计,并通过实验研究进一步证实该设计方法具有先进性和实用性．将智能算法应用于机械优化设计,为该领域研究提供新思路．     

Optimum electrodeposition conditions of FeCoZr films with in-plane uniaxial anisotropy for high frequency application

FeCoZr soft magnetic films with amorphous structure were electrodeposited onto ITO conductive glass substrates from the electrolytes with different composition and deposition potential. The factors which affect the deposit composition were discussed. The in-plane uniaxial magnetic anisotropy of film intensively depended on the concentration of boric acid. The coercivity of thin films decreased significantly with the composition gradient of doping Zr element. The ferromagnetic resonance frequency was as high as 3.4 GHz. Therefore, these films have a wide range of applications in the high-frequency field.     

Relationship between tensile strength and preparation conditions for nickel foam

Abstract

The relationship between preparation conditions and tensile strength has been investigated for a nickel foam produced by electrodeposition on an organic foam. After sintering in a NH₃ decomposition atmosphere at 980°C for 40 min, the results show that the tensile strength is hardly influenced by burning in air at 600°C for 4 min beforehand, or by lowering the sintering temperature to 850°C. During conductive treatment of the organic matrix it was found that coating with graphite base conductive colloid or chemically plating with Ni–P alloy (～5 wt-%P) brought the same tensile strength for the eventual product.