Evaluate axial stiffness of the MERO connection, under the effect of hardening the screw

Abstract

Given that the networks of two or more layers Space structures with rotational joints connecting Mero joints  secondary role in the transmission, hardening effects on the relationship between the screw axial force - displacement plays a key role in the mechanical behavior of the network connection. And also the design of these structures instead of connecting the entire design in different positions,it is necessary to connect just a simple equivalent circuit  in a state of tension with the bolts and the pressure of the sheath and simple relationship between them can be found in the design. In the present discussion ABAQUS/EXPLICIT software and finite element method of three-dimensional effects of different amounts of hardening curves in connection with Mero on the axial force - displacement relationship difficulties connecting and binding and its components in tension and pressure conditions has been investigated . In this model the geometric nature of the spiral screw thread construction model to simulate the hardening of the screw is provided with multiple tightening moments actions.

The results showed that in these model different values ​​of hardening affected on the tensile force screw connection - connecting the shift and gradually with the increase in  the hardening of the screw connection, tensile stiffness in the linear range of binding behavior increased. It is noteworthy that after a range of hardening, the tensile stiffness increase the of the connection stops. Also the bolts attaching the equivalent of a quadratic relationship between them was placed on the design criteria.