###### Abstract
[15] proposed a method based on fuzzy grey relational analysis to determine the prioritization of maintainability indices, and the fuzziness and uncertainty of design factors are considered in their method. [PERSON] et al. [16] outlined a diagnostic approach to quantify the maintainability of a commercial-off-the-shelf-based system, and their method is given by analyzing the complexity of the deployment of the system components. [PERSON] [17] presented a virtual maintenance application for the maintainability analysis and evaluation of flexible cables, and recommendations on the maintainability of products containing cables can be obtained during the early stages of product design. A case study on aircraft system disassembly was used to validate the feasibility of the improvement for cable maintainability designs. [PERSON] et al. [18] developed an evaluation index system of product maintainability based on the theory of product life cycle. A maintainability calculation method was proposed with consideration of the inherent attributes and external factors simultaneously. [PERSON] et al. [19] proposed a design approach considering the relationship between maintainability and functional construction. A practical case was given by implementing the proposed approach for the lubrication system of an armored vehicle to validate the effectiveness and feasibility of the approach. The present maintainability evaluation methods can be divided into three types. The first is the time related methods based on the probability theory [1; 2; 3], the maintenance time is the only index considered in these methods. The second is the process based method [4; 5; 6; 7], the maintenance process is modeled to support task demonstration in these methods. The last is the multiple attribute decision based method [8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19], different kinds of attributes are considered and maintainability deficiencies can be discovered with these methods. In all the above mentioned methods, logistic factors including the required tools or equipment, spare parts and maintenance personnel are seldom considered in the maintainability evaluation. The maintainability parameters can be divided into two types essentially. The first one is the time related parameters and the second one is the economic parameters. The first type of parameters includes MTTR and repair rate; and the second types of parameters includes direct maintenance man-hours per hour and direct maintenance cost per hour. The consumption of spare parts, the depreciation cost of tools or equipment, and the labor cost of maintenance personnel are closely related to the economic parameters. The requirement of system availability can be satisfied by controlling the time related parameters, and the economic efficiency of the system is realized by controlling the economic parameters. Therefore, both time and logistic factors should be considered in maintainability evaluations. As a graphical tool for discrete-event simulation, Petri nets have been widely used in process modeling, the specific application includes reliability and maintainability optimization [20; 21; 22], life-cycle cost analysis [23; 24; 25], production process modeling [26], and so on. Logistic factors are not considered in these studies either. The stochastic colored Petri net (SCPN) is extended from the classical Petri net by introducing colored tokens and stochastic timed transitions [27]. Compared with the classical Petri nets, the SCPN has two advantages in the modeling of the maintenance process simulation. Firstly, colored tokens can be applied to denote different kinds of maintenance resources as well as system states; secondly, timed transitions can be applied to denote maintenance tasks with time attributes. In this study, a maintenance process model is developed by using the SCPN. Approaches for calculating the required maintenance resources as well as maintenance time are proposed by using the maintenance process model.