Papers by Keyword: Mechanism

Abstract: The slump loss of fresh concrete mixed with superplasticizers should be well controlled to ensure its transportation and pumping. In this paper, we describe a comprehensive overview of the mechanism of fluidity loss and then analyze the reason for the change. Researches show that the slump loss of fresh concrete is influenced by the mineral composition of cement clinker, the type and characteristics of aggregate, the species and dosage of admixture, the mix proportion and the construction environment, etc. Thus, a series of methods proven to be effective, such as adjustment of raw materials, adding methods of chemical admixture, synthesis of new types of superplasticizers, etc. have been proposed to solve the problems.

Abstract: Steel slags are byproduct of steel making process in blast oxidizing furnace (BOF) and electric arc furnace (EAF), including BOF slag, EAF slag. Residual slag mud is discharged after recover of iron from steel slag by magnetic separation after a wet grinding process. The wet disposal process has higher efficiency than dry process but would deteriorate cementitious reactivity of wet residual mud. For residual EAF slag mud and residual BOF slag mud have different composition, effects of wet disposal process on their reactivity and hydration mechanism of related cements were researched in the paper. Analyses of microstructure and testes of mechanical properties for cements from the two different mud showed that the cements composed of 25 % of different mud respectively can reach the national standard of 42.5 grade cements. But residual EAF slag mud has better reactivity. Cement composed of residual EAF slag mud had a higher increase of compressive strength during 28 days of hydrations, and fluffy C-S-H gel and needlelike AFt crystal would increase obviously. Reactivity of BOF slag would degraded more in wet disposal process for its quicker hydration than EAF slag which resulted in more Ca(OH)₂ and C-S-H gel formed in the discharged mud,. EAF had lower basicity, content of less f-CaOand C3S, more P₂O₅ and C2S, which would contribute to its stability in the wet disposal process. EAF slag is more suitable for wet-disposal process.

Abstract: This research presents the use of a computer oriented numerical approach in the characterization of a parallelogram mechanism used on automobile windscreen wipers. The aim is to perform a kinetostatic analysis for obtaining through numerical simulations the joint reaction forces for a parameterized mechanism. Based on a combination between classical methods and computer simulations using Multi-body System method, the friction forces between wipers blades and windshield will be evaluated. The obtained results add new contributions on automobile windshield wiper mechanism design and analysis.

Abstract: The aim of the thesis is to describe of building elements Bond Graph methodology for modeling dynamic systems. Technique of Bond Graph methodology for modeling dynamic systems is demonstrated and its place in the process of modeling of mechanic and electric system and its behavior is discussed. The building elements of bond graphs as source effort and flow, capacitor, resistor, inductor, gyrator and transformer are described.

Abstract: The main reason for the choice of this theme is the extension of use of valve mechanisms and the possibility of using the new simulation program MSC Adams. The aim of this paper is to become familiar with the problems of the valve mechanism, the dynamic analysis and computer simulation. In this paper we described an overview of the problems compiling a mathematical model of the mechanism of the valve timing. After creating a mathematical model was made in the simulation program MSC Adams/View. The equation of motion of a mechanical valve mechanism was compiled Lagrange equations second order. The actual solution procedure that is mentioned in this paper can be applied to solve complex problems and shape of the valve mechanisms.

Abstract: This paper presents the calculation of dynamic parameters of virtual prototype of mechanism, which function is the correct tensioning of wedge belt of belt gear. Sudden release of tensioning device usually occurs during the assembly process, large impact forces which form have destructive effect on the device. A part of the paper will be the analysis of input parameters for solution by function Impact. Impact effects will be solved with flexibility of chosen member of the mechanism in mind. The solution will be realized in the environment of software MSC.ADAMS and ANSYS.

Abstract: The aim of this article is to develop a functional model of the crank mechanism with a rotating cylinder in MSC Adams/View software and its complete kinematics analysis. We analyze the movement of the members of the mechanism. Kinematic analysis was performed analytically and graphically. Finally, the work presents the results with graphical representation of parameters such as displacement, velocity and acceleration as well as angular velocity and angular acceleration in Adams/View.

Abstract: Cotton fabrics are very popular textile products to consumers due to their soft hand and comfortable wearing performance. However, the severe wrinkles on cotton fabrics will frequently happen after washing or wearing. As the growth of the market and demand of consumers, the sales of the steam ironing machine which can remove wrinkles to some extent is getting better. At present, the research is inadequate on the wrinkling mechanism during steam ironing. Therefore, in this paper, we aimed to investigate how cotton woven fabrics’ performance influences on the smoothness appearance after steam ironing. To further analyze wrinkling mechanism, fabrics’ wrinkle recovery rates which comprehensive characterize the physical and mechanical properties were tested with PhabrOmeter, including wrinkle recovery rates at normal temperature and after high temperature treatment. Then, the effect of temperature to fabrics’ wrinkle recovery rates and its relationship with fabrics’ smoothness appearance after ironing were studied. The results indicate that there are no significant correlations between the fabric basic parameters with smoothness appearance after ironing. The effect of temperature during ironing can improve the wrinkle recovery rates about 6%-21%. And no significant correlation is showed between smoothness appearance after ironing and wrinkle recovery rates. Keywords: Steam Ironing; mechanism; fabric parameters; wrinkle recovery rate.

Abstract: This paper describes the design process of a high-speed cutting press with a linkage mechanism in its drive train. The whole process is carried out for a virtual prototype. The kinematic and dynamic properties of the six-bar linkage mechanism are optimised regarding boundary conditions coming from the production process and kinematic requirements. Using a rigid body model, the geometric dimensions and inertia parameters of the links of the mechanism can be determined. A finite-element (FE) model is build up to check the parts’ durability during work load. A verification of main results is realised on an experimental prototype made from rapid prototyping material.

Abstract: The deformation and mechanical properties of Zr-based bulk metallic glasses (BMGs) under a nanoindenter and the effect of cooling rate, the effect of cooling rate, tungsten fiber addition and annealing on them have been studied by means of a nanoindentation instrument and a scanning electron microscope (SEM). The results indicate that the deformation of Zr-based BMGs under a nanoindenter is characterized by multiple shear bands and viscous flow which confirms the existence of a amount of plastic deformation. For pure quenched Zr-based BMGs, the larger the size of samples or the nearer the location away from the surface of a same sample, the smaller the values of microhardness (Hv) and elastic modulus (E); Annealing and tungsten fiber addition enhance the values of Hv and E; meanwhile, they also significantly change morphology around a nanoindenter and the amount of plastic deformation. The mechanism of plastic deformation is preliminarily analyzed.