We prove that when the homotopy map is a regular map,the K-K-T point obtained from this homotopy method must be a local optimal solution by choosing proper homotopy equation.

As one of the most fundamental joint configurations in tubular structures, The ultimate capacity of planer gap tubular K-joints is insufficient sometimes, which limit the project application of steel tube-truss.

Thus, an analytical parametric study was conducted to investgate the behavior of uniplanar K-joints and multiplanar KK-joints.

Necessary and sufficient conditions for the K-T points to be the minimum points and for weak duality of a type of non-smooth programming problem;

Firstly,with the help of Lagrange function and F-B function of NCP,it sloves general constraint optimization problem by constructing the linear equations of equating K-T point condition.

Based on the K-T condition,it is verified that the center method can obtain at least the K-T point for the multi-objective optimization,whose result founds the basis for the research of Pareto optimality.

Study on Collision Behavior of K-joint in Offshore Jacket Platform;

Experiment on Force Performance of Concrete-filled Rectangular Steel Tube K-joints;