In this work it is studied the influence on the spot clinching formation of the adhesive thickness for hybrid lap joints of adhesives with and without capability of full up –polyurethanes and ...cyanoacrylates - applied on galvanised and painted sheets. The results of static tests and the mechanisms of fracture are also influenced by the adherents thickness. In fracture analysis, performed with optical and electronic microscopy, fatigue characteristics are very difficult to observe on polyurethanes, but they can be seen, on the contrary, with quite evidence on cyanoacrylates. Fatigue behaviour analysis were very satisfactory, with fatigue limits over the range of 40% to 50% of the respective static resistance, depending on the cases.
Se estudia la influencia en la formación del encastre (“clinching”) del espesor de adhesivo en uniones híbridas a solape, para adhesivos con y sin capacidad de relleno -poliuretanos y cianoacrilatos - en chapas galvanizadas y prepintadas. Los resultados en ensayos estáticos y mecanismos de rotura son también influidos por el espesor de los adherentes. En los análisis de fracturas, realizados por microscopia óptica y electrónica, las características de fatiga son difícilmente observables para los poliuretanos, mostrándose, por el contrario, con bastante evidencia para los cianoacrilatos. Los análisis de los comportamientos en fatiga fueron muy satisfactorios, con límites de fatiga del orden del 40% al 50% de las correspondientes resistencias a carga estática, según los casos.
This chapter provides information on various aspects for optimum design and improved performance of adhesively bonded joints in structural applications. They include joint configurations, joint ...design parameters, substrate properties and adhesive selection. Methods to improve joint performance by adhesive layer modification, substrate shaping and hybrid joining are presented.
Traditionally, discrete robot's performance in flexibility and obstacle avoidance is not very outstanding, while continuum robot cannot load much and its motion space is limited. In this paper, a new ...robot with hybrid joints was designed based on the two kinds of robots mentioned above. First, the connection mode between discrete and continuum joints was analyzed. It was found that when the axis of the discrete joint was vertical to the tangential direction of the continuum one, the robot's motion space could be extended. Second, the driving modes of continuum and discrete joints were introduced, and it was also introduced in detail how the continuum joint was controlled by the external ropes. Then the analysis of the dynamics model and kinematics simulation of the continuum joint was carried out, and it was found: There is effect on the control by gravity, and in the same condition, the tension of ropes is relatively larger with gravity. While the continuum joint can move smoothly without gravity and the effect by gravity does not change over the increase of the degree of elastic rod.
In this paper, robust force/motion control strategies are presented for mobile manipulators under both holonomic and nonholonomic constraints in the presence of uncertainties and disturbances. Robust ...controls are proposed based on a simplified dynamic model, the defined reference signals and the mixed tracking errors. The proposed control strategies guarantee that the system motion converges to the desired manifold with prescribed performance. Constraint force control is developed, which does not utilize force feedback control but is based on the passivity of hybrid joint. Experiment results validate not only the states of the system asymptotically converge to the desired trajectory but also the constraint force asymptotically converges to the desired force
PDF
