Papers by Keyword: Mechanical Model

Abstract: The quality of a part produced using stamping process is dependent on many parameters such as the geometries of the tools and the initial blank, their surface state, the clamping force or contact pressure, the tools velocity and the lubrication. In order to discriminate different lubricants for stamping process in automotive industry under various conditions of clamping force and punch velocity, the Swift cup drawing test is used to evaluate the performance of three lubricants, i.e., two oil-based liquids and one dry film, applied on AA5182-O sheets. Moreover, finite element simulations are used to estimate friction coefficients of these lubricants.

Abstract: In this paper a mechanical model of the car and the related mathematical model are presented. Based on this mathematical model, some kinematic and dynamic parameters of the car are determined when moving between milestones. These theoretical results are compared with the experimental results to validate the proposed model.

Abstract: NiTi shape memory alloy (SMA) vascular stent, with good bio-compatibility and super-elastic properties, has become an important medical device in clinical treatment of cardiovascular or cerebrovascular diseases. The free expansion of stent in vessel involves the mechanical behavior of geometric large deformation related to the structure of super-elastic. In this paper, the nonlinear mechanical model for the substructure of NiTi shape memory alloy vascular stent is established, and the displacement deformation equation is derived. The geometric non-linearity of the structure is proved. Furthermore, the geometric nonlinear mechanical model is verified by numerical method. The mechanical analysis model of NiTi shape memory alloy vascular stent is widely used in the field of tracheal stent and so on.

Abstract: Wire sawing with diamond tools is a highly flexible cut-off grinding process with regard to machinable component structure and composition. Nowadays, it is deployed in many fields of application e.g. the dismantling of nuclear or industrial plants. Here, steel has to be cut which results in lower productivity and tool life compared to the conventional processing of natural stone. To ensure a properly designed process the mechanical and thermal tool loads have to be known in advance. This paper presents an analytical model that predicts the mechanical load as a function of the process parameters.

Abstract: During milling of thin-walled components, obtaining minimum distortion is essential in order to achieve production goals. In this study, a mechanical model based on deformation machanism is established, and is help to analyse relationship between residual stress and deformation in component. Researched on simulation and experiment, the stress-deformation characteristics of different component shape is obtained. The results indicate that the deformation of thin-walled component in milling primarily depends on the distribution of initial residual stress, which can generate bending moment and lead to distortion. And then milling stress on the surface is easy to make bending moment baesd on this distortion, and make the deformation of component intensify.

Abstract: The semisolid shear rheological characteristic of AZ91D alloy were investigated. The results show that: during the shear rheological test at 570 °C, a critical shear stress and a maximum shear stress are happened. And with holding time increasing, the solid fraction decreasing and the solid particles distributing more uniformly, the rheological rate increases but the critical and maximum shear stress decrease. At last, based on rheological theory, a five-component rheological model of the semisolid AZ91D alloy is established, which is H1 - (N1 / H2) - (N2 / S).

Abstract: The microbead modified super sulfate cement (SSC) was employed to prepare C60~C80 concrete, this work emphasis on mechanical properties and micro-mechanism, besides, the service behaviors of fresh concrete was tested. The SSC concrete mechanical properties influenced by particles size of microbead, slag and gypsum were discussed. Mechanisms of mechanical properties changes were elaborated from micro, meso and macro scales, mechanical model was established and relevant rules of mechanical properties development were obtained. Experiment results show that compressive strength increased with the largerer specific surface area of microbead, slag powder and gypsum. There was a promoting effect for SSC concrete hydration reaction by appropriate dosage (10%~20%) of microbead, which had prominent interstitial effect and system with excellent gradation, and fresh concrete workability was significantly improved. The compressive strength—curing ages model of high strength SSC concrete was established by half value intensity index, which coincide well with measured values. Key words: super sulphated cement concrete, microbead, mechanical properties, mechanical model, specific surface area

Abstract: Build the mathematical model and mechanical model of ultrasonic motor which using bending vibration transducer. Based on this model, analyze the contact and friction processes between driven-foot which belonging to ultrasonic motor which using bending vibration transducer and guide rail. Analyze the influence preload force make to the process of motor’s running. Take the cases of stick, slip, flight into consideration, and explain nonlinearity of the Dynamics. Do computer simulations of starting process though this model, and summarize the motor’s working results when it works under different conditions.

Abstract: When the long-distance oil pipeline under rivers (referred to as river-crossing pipelines) are damaged by the third-party, they are prone to nudity or left vacant, and the oil pipelines under the action of water flow will cause pipeline failure; and the distance of suspended pipeline is longer than the allowed length will cause the pipeline resonance. In order to avoid pipelines fatigue or broken, suspended pipelines are considered as part of the arc shape, and non-suspended pipelines are considered as the linear shape of the mechanical model with the two ends of the fixed pier synchronous. The study will consider the impact of water flow, buoyancy, the gravity of pipelines and its annexes, bending deformation and bending moment, do the tense calculation for suspended pipelines with external load and the vibration analysis for suspended pipelines under different water flow speeds. The results showed that: the design of river-crossing suspended pipelines not only needs to consider the impact of water flow, buoyancy, the gravity of pipelines and its annexes, bending deformation and bending moment, but also to consider the floating vortex-induced vibration of the suspended pipeline, which should cause pipeline designers, constructors and maintainers’ attention.

Abstract: To design a set of force-applying mechanism, simulate the stresses of workbench in vertical milling process and complete dynamic test of performance parameters by controlling the mechanism on the basis of the research of a testing stand of precision preserve of rolling functional components. This paper establishes a mechanical model to simulate the milling stresses of workbench, and makes use of the principle of the force and moment equal to deduce the functional relationships between the force of mechanism applying and the milling force, makes appropriate transformation according to the working principle of force-applying mechanism; adopt the “PC+NC” NC system architecture and use VB complete programming of the testing stand open NC system based on the multiple axis controller PMAC. Operators can achieve the function of testing stand by the established system interface. In the process of the test of performance parameters by testing stand, the force-applying mechanism applies milling force which could ensure test data accuracy and also save energy.