PSI - Issue 13

I. Shardakov et al. / Procedia Structural Integrity 13 (2018) 1324–1329 Author name / Structural Integrity Procedia 00 (2018) 000 – 000

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behavior of a flange joint, Abidelah, et al (2012), Blachowski and Gutkowski, Li et al (2018), Prinz et al (2014), Roudsariand et al (2018). Each version of the flange connection has its own peculiarities of the deformation behavior, which become especially significant under inelastic deformation. In the engineering environment, the development and implementation of verified mathematical models that allow analyzing the deformation processes in the elements of flange connections from the elastic state to the complete loss of bearing capacity is an urgent issue. This paper presents a series of experimental and theoretical studies conducted to analyze the specific features of quasistatic deformation processes in bolted flange connections. Mathematical modeling of the stress-strain state of the elements of such connections is complicated by the following three factors: three-dimensional geometry of mating parts, contact interactions between the bolted connections at the stages of their installation and operation, and the availability of large elastoplastic deformations. The first challenge has been overcome through the use of the FEM software, but the remaining two have required the performance of a number of experimental and theoretical studies to provide a reliable mathematical modeling of the stress-strain state in the elements of this joint.

2. Experiment description

The schematic drawing of the sample of the flange connection is shown in Fig. 1. The sample consists of a vertical column and two symmetrically located horizontal beams adjacent to it. The horizontal beams are connected to the vertical column by eight bolts. The I-Beam shape of the beam and column is considered.

Fig. 1. The diagram of the flange connection (dimensions are in millimeters)

For the experimental study of the deformation processes in the connection elements, a test stand has been developed. The structural diagram of the stand, the load scheme and the system for measuring during the tests are shown in Fig. 2a. The sample consisting of a column 3 and a beam 4 is loaded in the power frame 1 using hydraulic jacks 5 connected to the common hydraulic line, which ensures symmetrical loading of the sample throughout the experiment. The figure shows: F, 2F – reaction forces arising, respectively, in the horizontal beams and the column from the action of the jacks; U1, U2, U3 – location of vertical displacement sensors; E1, E2 – location of sensors for measuring deformation in a horizontal direction, EF – location of sensor for measuring deformation along the beam axis. Relative to the independent reference base the vertical displacements of the horizontal beams in the vicinity of the places of application of forces from the hydraulic jacks, as well as the vertical movement of the lower end of the vertical column, were measured. Such a scheme for measuring vertical displacements made it possible to control the symmetry of the deformation relative to the vertical column, and also to determine the value of the vertical displacement of the column only due to the entire set of the deformation processes in the flange connection. The positions of sensors E1, E2 on the vertical column and EF on the horizontal beam are determined from the results of mathematical modeling of the quasistatic deformation process in the framework of the elasto-plastic deformation. The E1, E2 sensors are designed to record the dominant strain values along the horizontal axis on the shelf of the vertical column. The EF sensor is fixed on the upper shelf of the horizontal beam at a distance of 33 cm from the flange. Such a position of this sensor ensures absence of plastic deformations and allows one to control the effort from the jacks.