# Experimental Studies on the Strength of a Flatar during Shunting Impacts
## 2 Analysis of Recent Studies and Publications
They proved that elastic interaction between the flatcar and the container decreased the dynamic loading in comparison with that of the standard diagram of interaction by 18%. However, they did not determine the load of the flatcar loaded with containers at the typical diagram of interaction. Of scientific value is the determination of dynamic load of the flatcar carried out by [PERSON] and [PERSON] [13]. The authors studied two loading diagrams for the flatcar: with displacements of the container relative to the frame during a shunting collision and without them. They determined how the displacements of the container affected the dynamic load of the container structure and the flatcar. However, no theoretical research was conducted, and the models were only verified by comparing the results of mathematical and computer modelling. [PERSON] et al. [14] carried out mathematical modelling of the load on the flatcar loaded with containers. The authors proposed a mathematical model that included the displacements of the containers relative to the frame during a collision and determined the acceleration values. This model included the longitudinal load of the flatcar with containers. Based on the results of the calculations, it was concluded that the accelerations acting on the flatcar with containers, if taking into account their compliance, were higher than normative values. The study into the load of the flatcar with containers was carried out by [PERSON] et al. [15]. The interaction between the containers and the flatcar was simulated by means of elastic-dissipative connection at a longitudinal load of 2.2-2.8 MN applied by means of a hammer car. The model included three levels of freedom for the containers: bouncing and galloping oscillations as well as longitudinal displacements. The authors took into account the effect of the gap between a fixed fitting of the flatcar and a container fitting on their dynamic load. The study also presents the dependency between the impact from the longitudinal force and the acceleration to the flatcar and containers. However, these studies have no experimental verification of the results obtained. [PERSON] and [PERSON] [16; 17] calculated the strength of the flatcar equipped with the rotating frame, where the flatcar was loaded with containers. The authors studied the main load diagrams for the flatcar frame. The calculation was completed with Ansis software using the finite element method. The strength results as well as the analysis of the stress distribution fields in the load-bearing structure of the flatcar are presented. However, the theoretical strength calculation was not verified experimentally. The special features of a nontrivial flatcar structure with an adjustable length of the frame are described in [18]. The flatcar frame consisted of separate structural blocks that were adjustable to the freight transported in length. That is, the structure was telescopic; the strength indicators of the operating modes were taken into account. Such a flatcar can be adapted to the transportation of containers. However, the authors did not describe the special features of the tests on the flatcar at operating modes. [PERSON] et al. [19] investigated the load of wagons, including flatcars with the expired normative service life. They also studied the possibility of extending the service life. The publication presents the results of determining the dynamics and strength of the flatcar by means of mathematical modelling in which the longitudinal and vertical load of the bearing structure of the flatcar was taken into account. The results obtained were integrated into the strength calculation of the bearing structure. However, the results were not verified experimentally. The review of literature sources makes it possible to conclude that the issue of experimental determination of the strength of the flatcar at the standard diagram of interaction between the fixed fitting and container fitting during a shunting collision has yet to be studied.