ABSTRACT
The effects of initial deflection are investigated, especially the coupling effect of multiple initial deflections. Numerical simulations with finite elements are conducted. For the pipelines with only one initial deflection, first, the effect axial position of initial imperfection is confirmed to have little influence. Secondly, the effects of the length and amplitude of initial deflection are tested. Then, multiple initial deflections are introduced into the pipelines. First, the effect of distance between two initial deflections with the same size is investigated, resulting in concluding the critical distance, which provides the criteria to judge the coupling effects. Therefore, the equivalent length of the coupled initial deflections is derived. Second, the effect of multiple initial deflections with different properties is investigated. Based on calculation results, an equivalent method is proposed to combined two adjacent initial deflection areas into one.
