Experimental and numerical verification of the pontoon bridge section

The object of the paper is experimental and numerical verification of a pontoon bridge prototype section. The main part of a single segment is a waterproof cassette which contains a shell (pontoon). After filling with the air, the pontoon assures the required buoyancy. The cassette, in which the shell is located, has a movable bottom. Pontoon bridges are built of ready-to-use repeatable segments and they may be used as temporary crossings. Verification of the bridge modules was performed by launching a demonstrator compound of two modules of the pontoon bridge section, filling the pontoons with air and measuring their immersion. The test was performed in the pool, in the Military Engineering Works. S.A. (WZInż. S.A.) in Deblin. Recording and measurements were performed with two Phantom V12 cameras placed on static tripods. It allowed reading from each of the cameras the heights of the midpoints of the prow and the starboard above the water surface, and the inclination angle of the pontoon unit in transverse and longitudinal planes. The combination of these results allowed calculation of height of the roadway centre of pontoons set above the water surface. Displacement and stability of the structure was specified based on analytical calculations. This paper presents the results of numerical calculations of launching a pontoon bridge section demonstrator. Correctness of the numerical methods of calculation was examined based on a comparison of numerical and experimental results

Modeling of the shock wave impact on the flexible shell

An underwater explosion is one of the possible threat which can occure during military operations and/or civilian usage. The ballistic protection systems are the method to reduce the impact of the high explosive (HE) charge blast wave. The aim of this paper is to present the influence of the shock wave on the flexible shell. The simulation of the underwater detonation is provided with use of the Finite Element Method (FEM). The influence of the distance between the HE charge and the flexible shell on its deformation was estimated. The results of the conducted analysis including explosion were compared with those obtained for the basic model with no explosion

Comparison of the dynamic riveting process of a rivet with and without a compensator

The paper deals with the analysis of deformation of a rivet hole in a riveted joint after the manual dynamic riveting process. For many years, riveting remains a traditional and the most popular method of joining in aircraft structures. The residual stress and strain state appear at the rivet hole after the riveting process, which improves the joint's fatigue behaviour. The local finite element models are made with Patron. The rivet and sheets are described using eight-noded, three-dimensional brick elements. The riveting tools consist of four-noded, two-dimensional shell elements. Numerical FE simulations of the upsetting process are carried out using the Ls-Dyna code. The contact with friction is defined between the collaborating parts of the specimen. The results of simulations of the dynamic riveting process of a mushroom rivet with and without a compensator are compared in this paper. Hole deformation of the upper and lower sheet, squeezing force, as well as deformations of the rivet head are analysed. The influence of the compensator on strain and displacement states is studied. Simulation shows that some technological factors may have positive influence on the residual stress fields. Using the rivet with a compensator results in a better rivet hole filling capability. The rivet hole displacement in upper and lower sheets are at the same level. Paper also present manual dynamic riveting process ofreverse and standard riveting procedure and model of riveted specimen

Comparison of the dynamic riveting process of a rivet with and without a compensator

The paper deals with the analysis of deformation of a rivet hole in a riveted joint after the manual dynamic riveting process. For many years, riveting remains a traditional and the most popular method ofjoining in aircraft structures. The residual stress and strain state appear at the rivet hole after the riveting process, which improves the joint's fatigue behaviour. The local finite element models are made with Patran. The rivet and sheets are described using eight-noded, three-dimensional brick elements. The riveting tools consist of four-noded, two-dimensional shell elements. Numerical FE simulations of the upsetting process are carried out using the Ls-Dyna code. The contact with friction is defined between the collaborating parts of the specimen. The results of simulations of the dynamic riveting process of a mushroom rivet with and without a compensator are compared in this paper. Hole deformation of the upper and lower sheet, squeezing force, as well as deformations of the rivet head are analysed. The influence of the compensator on strain and displacement states is studied. Simulation shows that some technological factors may have positive influence on the residual stress fields. Using the rivet with a compensator results in a better rivet hole filling capability. The rivet hole displacement in upper and lower sheets are at the same level. Paper also present manual dynamic riveting process of reverse and standard riveting procedure and model of riveted specimen