Reliability Allocation Method for Complex Agricultural Machinery Systems Considering Demand‐Side Response and Insufficient Fault Data Correction

Large‐scale agricultural machinery exhibits complex functionalities, limited test sample sizes, low fault data credibility, and urgent seasonal reliability demands, which challenge the precision of current reliability allocation methods. To better fulfill the reliability requirements of agricultural systems while accommodating industrial transformation and demand‐driven development trends in agricultural equipment, this study proposes a reliability allocation method tailored for complex agricultural machinery systems. Specifically, building upon structural–functional analysis and FMECA, an evaluation framework termed the 8B framework is established, comprising eight key indicators aligned with the characteristics of agricultural machinery. A multi‐factor maintainability definition method incorporating demand‐side response is proposed to quantify the feedback of user expectation deviations in reliability allocation. Using an improved TFN‐CRITIC‐IFM method for comprehensive weighting of the 8B framework, the weighting results are applied to the multi‐factor scoring matrix through slack factors, thereby establishing a failure rate allocation model for new products. Furthermore, a variable failure rate correction operator based on the parametric sigmoid function is introduced to characterize the dynamic approximation process of failure rate allocation results toward measured data, while avoiding excessive reliance on insufficient preliminary data with low credibility. A series system reliability allocation model considering demand‐side response and failure data correction is developed. The effectiveness of the proposed method is validated through a case study on a grain combine harvester.