Research of the reliability of a modular fire extinguishing system based on the forwarder Amkodor-2661

Forest fires are still a serious global problem. Therefore, designing of modern forest fire fighting machines is an important problem. This paper deals with the investigation of reliability of forest fire fighting system at the design stage by using fracture mechanics and possibility theory application. Usage justification and some advantages of using wheeled forwarders as basic machines for the installation of forest fire fighting systems are presented in the introduction. The basic fracture mechanics equations linking stress intensity factor with crack-like defect length are presented in the first part of the paper. Fracture toughness and crack-like defect length are viewed as Gaussian random values; maximum applied stress is presented as a fuzzy variable with unknown distribution law. Analytical equations for reliability evaluation are obtained by estimation of upper and lower bounds of reliability function. The real value of this measure is located within this interval. The estimation of reliability function by the example of the supporting frame of a modular firefighting system based on forwarder Amkodor-2661 is presented in the second part of the paper. The stress intensity was determined by the finite element method. The calculation is carried out for the variant of presence of an edge type of crack in material. The interval of reliability function values is calculated. It is important to know the upper value of failure probability and, accordingly, the lower one as the most provided value of reliability function. The proposed method may be used to assess the reliability of structural elements of forest machines with limited statistical information.