Buckling Experiments on Cylindrical Shells with Opening and Reinforcement under Axial Compression

Buckling experiments on cylindrical shells with opening and reinforcement under axial compression were studied. Axial compression data were read by weighing sensor, the 3D shape of shells was measured by a laser displacement sensor. The test results show that the opening can decrease the critical buckling load and the reinforcement can raise the critical buckling load of cylindrical shells under axial compression. Based on the measured data, the 3D finite element model was established. The simulation results show the critical buckling load of a cylindrical shell with an opening is larger than that of the cylindrical shell with reinforcement. It is in accord with the result of experiment. Introduction Cylindrical shells are widely used in many fields, and the buckling of cylindrical shells has been one of the most active subjects [1]. There is always an unacceptable large “error” between theoretical value and experiment, and the critical pressure of the early axial compressive cylindrical shells was only 1/5 ~ 1/2 of the classical linear theory, and the test results were very discrete [2, 4]. The engineering design is usually open all kinds of holes in the cylindrical shell, and causing geometrical discontinuities, not only enlarges the stress concentration of the opening edge, but also weaken the strength of shell structure and reduce the bearing capacity of the shell [5, 7]. Usually the reinforcement method is used to improve the bearing capacity, reinforcement is to increase the amount of metal that is weakened by openings around the hole, to reduce the stress in the local area around the hole, because the stress concentration occurs only near the hole and the stress is almost not affected by the hole in several times of aperture [8]. Containment is an important device in a nuclear power plant, there are many manholes, valve holes and penetrations in the steel containment, in this paper, the cylindrical shell section of the containment shell is used as a model, the small-scaled experiment and nonlinear finite element analysis [9] research on the buckling of cylindrical shell under axial compression were carried out. Although in the past there were many buckling tests of a steel cylindrical shell had been carried out [10, 11]. However, these tests were smaller in size, in this paper, the buckling test platform and experiment models are large in size, and the diameter of the shells are up to 1000 mm, and the axial compressive buckling tests of cylindrical shells with opening and reinforcement were carried out respectively. The 3D shape of shells was measured by a laser displacement sensor. Based on the measured data, the finite element model was established to simulate the experimental conditions and compare with the experimental results. Experiment Test Platform A special platform for axial buckling test is adopted, which is composed of a fixed table and a movable table with a central hole. The movable table is connected with the liquid device for