The Strength And Fatigue Behavior Of Tension Pin-End Connection

Tension structure system, as a new-style spatial structure system rising in last twenty or thirty years, has the self-adaptation and balanced mechanics characteristic. And that most units in this structure are in a state of drawing is favorable to fully utilize the material strength. Because of these reasons, Tension structure system has caused the extensive concern of scholars in relevant discipline, such as structure, architecture, mechanics, etc. To guarantee the continuous stress circuit is a key to form tension structure system. In order to achieve above-mentioned purpose, there must be suitable nodal structural forms to guarantee enough pre-stress force exerted and make the forming of the continuous stress circuit possible.According to domestic and international study on tension structure at present, it is early and deeply to launch the research to the system of tension structure. Comparatively, there is less research to the tension connections due to three reasons. Firstly, there is no enough attention to the importance of connections in system analysis and structure design. Secondly, it is lack of the analysis means to tension connections. Thirdly, because the appearance and mechanical character of pinned connections is similar to bolt and rivet, it is considered there is indispensable to research the behavior of pinned connections. However, considering the importance of tension connections in tension structure system and the difference between tension pin-end connections and pinned connections defined in norm, it is necessary to launch the research to bearing capacity of tension pin-end connections in order to underpin the validity.Based on the basic theory, such as testing theory, elastic mechanics, the non-linear finite element theory of solid mechanics and fatigue and theory, etc., the experimental, analytical and numerical means have been adopted in this thesis. Ideally, research on structural connections should be conducted through experimental, analytical/theoretical, and numerical means. Reliable test results are fundamental and underpin the validity of all subsequent theoretical and numerical work. Analytical/ theoretical work is important, because it often leads to the development of relatively simple design models that can be used routinely by structural engineers. Numerical modeling (finite-element analysis) is often important, for, if successful, it provides a means of carrying out wide-ranging parametric studies to complement existing experimental results. The main concern of the experiment is to observe the ultimate strength and failure pattern of tension pin-end connections at theultimate state when the influential geometrical parameters are varied. And the simple and feasible design formula and suggestions is proposed in the theoretical work.Rigorous finite-element modeling of tension pin-end connections must take into account effects of large deflection, material nonlinear and contact between pin-block, gusset-block and pin, pin/pin-block yielding, deformation and failure. This thesis describes the finite-element modeling philosophy employed to analyze the ultimate strength of tension pin-end connections. There are many subtleties and details to be resolved if an accurate simulation of tests is to be achieved. The effect of friction coefficient between the interface of pin, pin-block and gusset-block were investigated.It is worthwhile to research the fatigue behavior of tension pin-end connections. The main concern of the fatigue tests is to observe the fatigue behavior of tension pin-end connections under cycle loading when the influential geometrical parameters are varied. Due to the complexity of fatigue mechanism, the fatigue research in this thesis is very elementary. In addition, an elastic mechanics method is proposed to solve the plane pin-block in this thesis.