OBJECTIVE To assess the role of the glycoprotein PRG4 in joint lubrication and chondroprotection by measuring friction, stiffness, surface topography, and subsurface histology of the hip joints of Prg4(-/-) and wild-type (WT) mice. METHODS Friction and elastic modulus were measured in cartilage from the femoral heads of Prg4(-/-) and WT mice ages 2, 4, 10, and 16 weeks using atomic force micr...

In the complex engineering structures the use of bonded joints are often preferred to more traditional methods of fabrication such as bolts and welds since they are lighter and spread load more evenly. For determination the durability of such structures it is necessary to know well the stress field around stress concentrators. At the free edge of bonded joints between the adhesive and the adher...

A three-dimensional finite element modeling is developed using ABAQUS software. This includes riveted and rivet-bonded joints models. Both models undergo thermal heat caused by hot-driven rivet process and then are subjected to a constant velocity at one of its strip edges to simulate the shear tensile test up to the failure point. The developed FE models were based on elastic-plastic propertie...

A mesh independent continuum damage model has been proposed to predict the residual strength of adhesively bonded joints by introducing a displacement-based damage parameter into the constitutive equation of damaged materials. Joints bonded with a ductile adhesive EA9321 were studied for a range of environmental degradation. The moisture dependent damage parameter for EA9321 was calibrated usin...

Original scientific paper To analyse the influence of joint angle, number and spacing on the strength and acoustic emission (AE) characteristics of rock mass, the uniaxial compression model of rock specimens was established using the micro particle flow PFC2D software platform. The intact rock parameters were determined via trial and error, joints with different angles, numbers and spacing were...

The leaky Lamb wave (LLW) technique is approaching a maturity level that is making it an attractive quantitative NDE tool for composites and bonded joints. Since it was first observed in 1982, the phenomenon has been studied extensively, particularly in composite materials. The wave is induced by oblique insonification using a pitch-catch arrangement and the plate wave modes are detected by ide...

The paper presents a methodology for the enhanced stiffness analysis of parallel manipulators with internal preloading in passive joints. It also takes into account influence of the external loading and allows computing both the non-linear “load-deflection” relation and the stiffness matrices for any given location of the end-platform or actuating drives. Using this methodology, it is proposed ...

In this paper is presented the development of an indirect force control for robot manipulators with elastic joints employed in machining tasks. Based on the study of centralized compliance control for rigid manipulators, it is proposed an extension for robots with torsional flexibility in the joints structured as a cascade control. Additionally, it is proposed a reduced force model, based on ex...

This study presents the optimal drift design method to control the elastic and inelastic performance of steel moment frames. This is formulated as a problem that minimizes the lateral displacement at the top of a building satisfying the constraints on the total structural weight and the column-to-beam strength ratios at the joints. This uses the resizing method based on the linear static analys...

All over the world it can be noticed that the product miniaturisation is a central theme in product development for different application areas. In robotics scientific research one of the most important approaches is concerning the raise of the positioning accuracy by the use of parallel structures. The progress of the industrial production, especially the development of the industrial robotics...