An energy criterion for estimating the wheel stability reserve from the rolling of the flange onto the railhead during the motion of a wheel set along a straight section
In case of hunting, the lateral forces are created by pressing the wheels against the rails, which can lead to the wheel flange rolling onto the railhead and subsequent derailment. The derailment of the rolling stock poses a serious threat to traffic safety. The current standards for the calculation and design of railcars for 1520 mm gauge railways provide for checking the wheel stability from rolling onto the railhead. The minimum value of the safety factor of the wheel stability against derailment is taken as a criterion. The stability coefficient is determined based on the condition of the return of the wheel rolled onto the railhead to its original position under the action of the vertical force created by the weight of the railcar. In modern mechanics, most of the calculation methods are based on energy principles, which constitute the so-called "analytical mechanics" - an alternative to "vector (Newtonian) mechanics". A proposed method is to assess the stability of a wheel based on the condition of preventing the wheel flange from rolling onto the railhead by comparing the kinetic energy of the wheel set hunting with the work of the vertical and horizontal forces acting on the wheel set. The stability condition for the wheel is determined from the principle of preventing the wheel flange from rolling onto the railhead. The calculations of the variants of the movement of the railcar at different speeds were carried out based on the normative and proposed methods. A comparison of the critical (permissible) speed of movement was made according to the above methods. Comparative analysis showed that when assessing stability by the energy criterion, the permissible speed of the railcar is higher than with the force method. It may allow increasing the estimated speed tolerance of the designed railcar with further detailed analysis and assessment of all the dynamic factors of the railcar.