Deformation and stress analysis of a U-shaped pipe compensator using a 3D scanner

The paper shows a comparison of the three different methods to determine stress and strain in a U-shaped pipe compensator which is used to decrease stress in long pipes due to the constrained temperature dilatations. The stress and strain are analyzed analytically first with some parts of the analytical solution obtained numerically, such as integrals with no analytical solution in a closed form, i.e., functional series can be involved as a tool to solve those integrals. The pipe is analyzed as a beam or a planar frame using the Castigliano's method to determine displacements. Since there are curved parts of the U compensator, the curved beam theory is applied. The alternative method to determine the strains and stresses along the pipe is shown using the numerical simulations in SolidWorks. The results are compared with the analytical solution. Finally, the experimental method using a 3D scanner is involved for a comparison to check the applied conditions in the analytical and the simulation model

Underwater explosion effects of 60 mm H.E. mortar bomb on a cylindrical concrete structure - PIT

PIT tests are usually performed when a mass distribution of High Explosive (H.E) projectile fragments is required. This paper shows the underwater detonation effects of 60 mm, M90 H.E. mortar bomb filled with Comp. B on cylindrical concrete structure (concrete pipe closed at one end - similar to a PIT test) which is 2 m high (inner height) with inner diameter of also 2 m. Thickness of both wall and bottom of a pipe is 0.35 m. Detailed characteristics of concrete which is used for manufacturing of a pipe are specified. Mortar bomb is submerged directly in to the water (no free airspace around the bomb) with the nose pointing to the bottom of a pipe. Number and mass of fragments after detonation are presented by table and photographs. Fragments of dummy fuze, through which blasting cap was protruded, are collected and reassembled to form a shape of a fuze after detonation where expanding of fuze material due to a detonation products is visualized. After underwater detonation, detonation of the same mortar bomb is performed in an empty pipe and the effects of this kind of detonation are observed. Distance at which fragments generated from submerged mortar bomb will not reach concrete pipes wall is also determined. Keywords: Underwater explosion, Mortar bomb, Blast, Comp B, Dummy fuze, Fragment