Encontrados 35 documentos, a visualizar página 1 de 4
Experimental comparison of the performance of a journal bearing with a single a...
Brito, F. P.; Miranda, A. S.; Claro, José Carlos Pimenta; Fillon, M.It is often assumed that a journal bearing will operate more effectively with a twin groove arrangement than a single groove one, but little evidence has been presented in support of this. An experimental assessment of a journal bearing with either one or two axial grooves located perpendicularly to the load line was performed. It was found that under heavy loaded operation the twin groove configuration might a...
An experimental study of the influence of loading direction on the thermohydrod...
Arab-Solghar, A.; Brito, F. P.; Claro, José Carlos Pimenta; Nassab, S A GandjalikhanAn experimental assessment of the influence of the angle between the groove axis and the load line on the thermohydrodynamic behaviour of twin groove hydrodynamic journal bearings has been undertaken. At nine different loading direction angles, the oil–bush interface temperature profiles, oil outlet temperature, maximum bush temperature, total flow rate, and oil flow rate through each groove were measured for v...
The role of lubricant feed temperature on the performance of twin groove journa...
Brito, F. P.; Miranda, A. S.; Claro, José Carlos Pimenta; Fillon, M.An experimental assessment of the influence of lubricant feed temperature (Tf) on the behaviour of twin groove hydrodynamic journal bearings has been undertaken. Several loads, shaft speeds and bearing geometries were tested under constant lubricant feed pressure (pf), while Tf took four different values between 29ºC and 58ºC. It was found that the increase of Tf has an effect in bearing performance which is an...
Development of a planar multi-body model of the human knee joint
Machado, Margarida F.; Flores, Paulo; Claro, José Carlos Pimenta; Ambrósio, Jorge; Silva, Miguel; Completo, António; Lankarani, Hamid M.The aim of this work is to develop a dynamic model for the biological human knee joint. The model is formulated in the framework of multibody systems methodologies, as a system of two bodies, the femur and the tibia. For the purpose of describing the formulation, the relative motion of the tibia with respect to the femur is considered. Due to their higher stiffness compared to that of the articular cartilages, ...
Lubricated revolute joints in rigid multibody systems
Flores, Paulo; Ambrósio, Jorge; Claro, José Carlos Pimenta; Lankarani, H. M.; Koshy, C. S.The main purpose of this work is to present a general methodology for modeling lubricated revolute joints in constrained rigid multibody systems. In the dynamic analysis of journal-bearings, the hydrodynamic forces, which include both squeeze and wedge effects, generated by the lubricant fluid, oppose the journal motion. The hydrodynamic forces are obtained by integrating the pressure distribution evaluated wit...
Translational joints with clearance in rigid multibody systems
Flores, Paulo; Ambrósio, Jorge; Claro, José Carlos Pimenta; Lankarani, H. M.A computational methodology for dynamic description of rigid multibody systems with translational clearance joints is presented and discussed in this work. Over the last years, extensive work has been done to study the dynamic effect of the revolute joints with clearance in multibody systems, in contrast with the little work devoted to model translational joints with clearance. In a joint with translation clear...
Dynamic behaviour of planar rigid multi-body systems including revolute joints ...
Flores, Paulo; Ambrósio, Jorge; Claro, José Carlos Pimenta; Lankarani, H. M.This paper deals with a general methodology to assess the influence of the clearance size and the friction coefficient on the dynamic response of planar rigid multi-body systems including revolute joints with clearance. When there is a clearance in a revolute joint, impacts between the journal and the bearing can occur, and consequently, local deformations take place. The impact is internal and the response of ...
Kinematics and dynamics study of a hexapod robotic system using computational p...
Flores, Paulo; Claro, José Carlos Pimenta; Ribeiro, António FernandoThe main purpose of this work was to perform kinematics and dynamics analysis of a prototype of an autonomous hexapod robot. This paper reports on an initial phase, where the basic geometry of the system was specified and improved through a kinematics and dynamic study by using a motion analysis software. This study also allowed the design of all mechanical components and the definition of motion generation nee...
A study on dynamics of mechanical systems including joints with clearance and l...
Flores, Paulo; Ambrósio, Jorge; Claro, José Carlos Pimenta; Lankarani, H. M.; Koshy, C. S.In this work a methodology for the dynamical analysis of mechanical systems considering realistic joint characteristics, namely, joints with clearance and lubrication is presented. For the case of the joints with clearance modelled as a contact pair with dry contact, a technique using a continuous approach for the evaluation of the contact force is applied, in which the energy dissipation in form of hysteresis ...
Influence of the contact–impact force model on the dynamic response of multi-bo...
Flores, Paulo; Ambrósio, Jorge; Claro, José Carlos Pimenta; Lankarani, H. M.This work deals with contact–impact force models for both spherical and cylindrical contact surfaces. The incorporation of the friction phenomenon, based on the Coulomb friction law, is also discussed together with an effective computational strategy, which includes the automatic step size selection procedure. Impacts within a revolute clearance joint in a basic slider–crank mechanism are used as an example to ...
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