Method for predicting disassembly and assembly time of turboshaft engine accessory based on maintenance process attributes

Abstract

The invention provides a turboshaft engine accessory disassembly and assembly time prediction method based on maintenance process attributes, which belongs to the technical field of maintenance engineering prediction, and comprises the following steps: carrying out maintenance task decomposition in combination with maintenance guidance information and kinematic decomposition of a time measurement method to obtain a maintenance task; obtaining a plurality of maintenance operation units and a plurality of basic maintenance actions in the maintenance operation units; performing six-dimensional maintenance attribute evaluation based on a language evaluation set on each basic maintenance action to obtain a corresponding six-dimensional time correction coefficient set; determining maintenance time of the plurality of basic maintenance actions by using a time measurement method; correcting the maintenance time of each basic maintenance action through the maintenance time correction model and the six-dimensional time correction coefficient set; and the corrected maintenance time of all the basic maintenance actions in all the maintenance operation units is calculated in an accumulated mode, and the turboshaft engine accessory disassembly and assembly time based on the maintenance process attributes is obtained. According to the method, the accuracy and practicability of the disassembly and assembly time estimation of the turboshaft engine accessory can be improved.

Description

Technical Field

[0001] This invention relates to the field of maintenance engineering prediction technology, and specifically to a method for predicting the disassembly and assembly time of turboshaft engine accessories based on maintenance process attributes. Background Technology

[0002] The time required for disassembly and assembly of accessories is a core indicator affecting the economic efficiency of turboshaft engine operation and is also a core component of maintainability forecasting during the design phase. Maintainability forecasting, based on a maintainability model, estimates whether the maintainability level achievable by the product design or design scheme can meet the specified targets, promptly identifying maintainability design and support deficiencies, and serving as a basis for design or support arrangements modifications.

[0003] Traditional methods for estimating maintenance time include probabilistic models, functional hierarchy, sampling scoring, operational functions, cumulative time, and unit comparison. However, due to insufficient historical data accumulation, most existing methods still rely on baseline times under ideal conditions, resulting in significant discrepancies between the estimated results and actual disassembly / reassembly operations. Especially during the design phase, the lack of accurate prediction tools limits the optimization and verification of maintainability design. Summary of the Invention

[0004] To address the shortcomings of the existing technologies, this invention proposes a method for predicting the assembly and disassembly time of turboshaft engine accessories based on maintenance process attributes. By introducing MTM-1 dynamic element analysis and combining it with six major maintenance attributes, a maintenance time correction model is constructed to predict the assembly and disassembly time of turboshaft engine accessories based on maintenance process attributes. This invention can effectively improve the accuracy and practicality of predicting the assembly and disassembly time of turboshaft engine accessories.

[0005] This invention provides a method for predicting the disassembly and assembly time of turboshaft engine accessories based on maintenance process attributes, comprising the following steps: S1. Combining the maintenance guidance information and time measurement method of turboshaft engine accessories, the maintenance task of turboshaft engine accessories is decomposed to obtain multiple maintenance work units and multiple basic maintenance actions in each maintenance work unit. S2. For each basic maintenance action obtained, a six-dimensional maintenance attribute evaluation based on the language evaluation set is performed to obtain the set of six-dimensional time correction coefficients S corresponding to each basic maintenance action: S=(K E K V K H K S K R K A ); Where, K E The basic maintenance action time correction factor considering error-proofing maintenance attributes; K VA correction factor for the basic maintenance action time considering the visibility maintenance attribute; K H A correction factor for basic maintenance action time considering human factors engineering maintenance attributes; K S A basic maintenance action time correction factor, K, is used to consider maintenance safety and maintenance attributes. R A correction factor for the basic maintenance action time considering the disassembly and assembly maintenance attributes; K A A basic maintenance action time correction factor that takes into account the accessibility maintenance attribute; S3. Based on the simulation of the maintenance process model of turboshaft engine accessories, the maintenance time of multiple basic maintenance actions is determined by the time measurement method. The maintenance time of each basic maintenance action is corrected by the constructed maintenance time correction model and the six-dimensional time correction coefficient set S, and the corrected maintenance time of the basic maintenance action is obtained. The maintenance time correction model is as follows: T= N MTM ×0.036s×(1+(K E +K V +K H +K S +K R +K A ) / 6 ) ; Where T is the maintenance time after correction of the basic maintenance action, and N is the maintenance time after correction of the basic maintenance action. MTM This refers to the number of basic time units required to complete a basic maintenance operation, calculated using time measurement methods. S4. Accumulate and calculate the corrected maintenance time for all basic maintenance actions in all maintenance work units to obtain the turboshaft engine accessory disassembly and assembly time based on maintenance process attributes. : ; Where i is the maintenance work unit number, i∈{1, 2, 3, ..., n}, n is the total number of maintenance work units obtained from the decomposition of the maintenance task; j is the basic maintenance action number, j∈{1, 2, 3, ..., m}. i},m i This represents the total number of basic maintenance actions in the i-th maintenance work unit obtained from the decomposition. The repair time is the adjusted repair time for the j-th basic repair action in the i-th repair work unit.

[0006] Furthermore, the six-dimensional maintenance attributes in S2 include error prevention maintenance attributes, visibility maintenance attributes, human factors engineering maintenance attributes, maintenance safety maintenance attributes, disassembly and assembly maintenance attributes, and accessibility maintenance attributes.

[0007] Furthermore, the language evaluation set in S2 includes a five-level language evaluation set Vs and a seven-level language evaluation set VT, where Vs = {excellent, good, average, poor, poor}; VT = {very good, good, fairly good, average, poor, poor, very poor}.

[0008] Furthermore, in S2, the error-proofing maintenance attribute, visibility maintenance attribute, human factors maintenance attribute, and maintenance safety maintenance attribute that significantly affect maintenance time are evaluated using a five-language evaluation set.

[0009] Furthermore, in S2, the disassembly and reassembly maintenance attributes and accessibility maintenance attributes that have a minor impact on the disassembly and reassembly operation process are evaluated using a seven-language evaluation set.

[0010] Furthermore, S1 combines the maintenance guidance information for turboshaft engine accessories with the dynamic element decomposition of the time measurement method (MTM) to decompose the maintenance tasks for turboshaft engine accessories, resulting in multiple maintenance work units and multiple basic maintenance actions within each maintenance work unit, specifically including the following steps: S11. Obtain the disassembly and assembly procedures for turboshaft engine accessories based on the maintenance guide information for turboshaft engine accessories; S12. Combining the obtained disassembly and assembly procedures and time measurement methods, the maintenance tasks of the turboshaft engine accessories are decomposed to obtain multiple maintenance work units and multiple basic maintenance actions in each maintenance work unit.

[0011] Further, step S2 evaluates each basic maintenance action based on a six-dimensional maintenance attribute set using a language evaluation set, obtaining a set of six-dimensional time correction coefficients S corresponding to each basic maintenance action. This specifically includes the following steps: S21. Determine the six-dimensional maintenance attributes that affect maintenance time; S22. Construct a five-language evaluation set and a seven-language evaluation set for evaluating six-dimensional maintenance attributes; S23. Construct a mapping relationship between the evaluation set and the evaluation values, transform the qualitative evaluation into quantitative values, and determine the basic maintenance action time correction coefficient corresponding to the evaluation values. S24. For each basic maintenance action obtained, perform a six-dimensional maintenance attribute evaluation based on the language evaluation set to obtain the set of six-dimensional maintenance time correction coefficients S corresponding to each basic maintenance action: S=(K E K V K H K S K R K A ); Where, K E The basic maintenance action time correction factor considering error-proofing maintenance attributes; K VA correction factor for the basic maintenance action time considering the visibility maintenance attribute; K H A correction factor for basic maintenance action time considering human factors engineering maintenance attributes; K S A basic maintenance action time correction factor, K, is used to consider maintenance safety and maintenance attributes. R A correction factor for the basic maintenance action time considering the disassembly and assembly maintenance attributes; K A The basic maintenance action time correction factor is used to take into account the accessibility maintenance attribute.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention innovatively constructs a maintenance time correction model. By finely decomposing maintenance actions and combining six major maintenance attributes—error prevention, visibility, human factors engineering, maintenance safety, disassembly and assembly, and accessibility—as well as a five-language evaluation set and a seven-language evaluation set, it achieves detailed and accurate correction of the time of basic maintenance actions.

[0013] 2. This invention constructs a mapping relationship between language evaluation sets and evaluation values, transforming qualitative language evaluation into quantitative values. This allows for the determination of the correction relationship between maintenance attributes and maintenance time during the maintenance process, providing a quantitative basis for maintenance time correction and laying the foundation for maintenance task time estimation. This further enables the estimation of quantitative indicators of maintainability during the design phase. Attached Figure Description

[0014] Figure 1 This is a flowchart of the method for predicting the disassembly and assembly time of turboshaft engine accessories based on maintenance process attributes according to the present invention; Figure 2 This is a schematic diagram of the disassembly and assembly procedure for a lubricating oil temperature sensor according to an embodiment of the present invention.

[0015] Key reference numerals: 1. Electrical plug; 2. Detector; 3. Sealing component; 4. Gearbox housing. Detailed Implementation

[0016] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0017] The following example, using the disassembly and assembly of an oil temperature sensor for the T700-GE-701D turboshaft engine as an example, illustrates the method of this invention and verifies its effectiveness. The T700-GE-701D is a high-performance military turboshaft engine developed by GE Aviation, and is an important development of its classic T700 series. While providing powerful thrust for helicopters, one of its core design principles is excellent maintainability, aiming to significantly reduce maintenance difficulty, shorten maintenance time, and reduce logistical support burden. The oil temperature sensor is installed at the front end of the accessory gearbox. This sensor detects the temperature and transmits the engine oil temperature signal to the engine temperature indicator.

[0018] As attached Figure 1 As shown, this invention provides a method for predicting the disassembly and assembly time of turboshaft engine accessories based on maintenance process attributes, which includes the following steps: S1. Combining the maintenance guidance information for turboshaft engine accessories with the dynamic element decomposition of the Time Measurement Method (MTM), the maintenance tasks for turboshaft engine accessories are decomposed to obtain multiple maintenance work units and multiple basic maintenance actions in each maintenance work unit. Specifically, the following steps are included: S11. Obtain the disassembly and assembly procedures for turboshaft engine accessories based on the maintenance guide information for turboshaft engine accessories; Turboshaft engine accessory disassembly and assembly are generally performed by a single person in a serial operation mode. Serial operation refers to a series of tasks that are consecutive, with the next task starting as soon as the previous one is completed, without overlap or interruption. In a maintenance event, an event consists of several maintenance work units, and each maintenance work unit consists of several basic maintenance actions. Under serial operation, the time to complete a maintenance event is equal to the sum of the times of each maintenance work unit and basic maintenance action. According to Task 41 of T700-GE-701D Engine Maintenance Manual 79-00-400C-002-9, the lubricating oil temperature sensor disassembly and assembly procedure is as follows: Figure 2 As shown, the above procedures are included.

[0019] Procedure 1: Disassembly.

[0020] Warning: Never use hard-jaw pliers to loosen the knurled connecting ring on the electrical plug. Doing so may damage the cable assembly.

[0021] (1) Disconnect the green cable electrical plug 1 from the mating plug on the oil temperature detector 2 by hand. If the electrical plug is difficult to loosen, proceed as follows: (a) Use soft-jaw pliers to loosen the knurled connecting ring on the electrical plug 1. (b) Disconnect the electrical plug 1 from the mating plug on the detector 2 by hand. (c) Cover both electrical plugs with protective caps. Note: In step (a), it is recommended to use padded soft-jaw pliers to loosen the electrical plug.

[0022] (2) Remove detector 2 from accessory gearbox housing 4.

[0023] (3) Remove and discard the sealing piece 3.

[0024] Program 2: Installation.

[0025] Warning: Never use hard-jaw pliers when tightening the knurled connecting ring on electrical plug 1, as this may damage the cable assembly. Never lubricate the electrical plug, as this may damage the electrical system.

[0026] (1) Install the sealing component 3 onto the oil temperature detector 2.

[0027] (2) Install the detector 2 onto the accessory gearbox housing 4 by hand tightening.

[0028] (3) Tighten detector 2.

[0029] (4) Install the green cable electrical plug 1 onto the mating plug of the detector 2, following these steps: (a) Remove the protective cover from the electrical plug. (b) Screw the knurled connecting ring on the cable plug into the mating socket connector by hand. If the connecting ring is difficult to screw in, check the connector for thread misalignment, bent pins, keyway damage, etc. (c) Alternate operation: Push the back cover of the cable plug into the socket while rotating the connecting ring by hand until the colored alignment mark is completely covered and the plug is fully inserted into the mating connector. Tighten the knurled connecting ring to the maximum tightness. (d) If the knurled connecting ring cannot be rotated beyond the colored alignment mark or to the maximum tightness, use soft-jaw pliers to rotate the knurled connecting ring to ensure complete coverage of the colored alignment mark and to bring the connector to the maximum tightness.

[0030] S12. Combining the obtained disassembly and assembly procedures and time measurement methods, the maintenance tasks of the turboshaft engine accessories are decomposed to obtain multiple maintenance work units and multiple basic maintenance actions in each maintenance work unit. The time measurement method referred to in this step can be, for example, the MTM method.

[0031] Time-based measurement methods (e.g., Method-Time Measurement, MTM) break down human maintenance actions into multiple basic actions, and further into dynamic elements. Combining the resulting disassembly and assembly procedures with the dynamic element decomposition of the MTM method, the lubricating oil temperature sensor disassembly and assembly procedure is broken down into two maintenance work units: disassembling the lubricating oil temperature sensor and installing the lubricating oil temperature sensor. The disassembly unit is further subdivided into 7 basic maintenance actions, and the installation unit is also subdivided into 7 basic maintenance actions, as shown in Table 1 below. Table 1: Breakdown of Repair Tasks for Lubricating Oil Temperature Sensor S2. For each basic maintenance action obtained, a six-dimensional maintenance attribute evaluation based on the language evaluation set is performed to obtain the set of six-dimensional maintenance time correction coefficients S corresponding to each basic maintenance action. This includes the following steps: S21. Determine the six-dimensional maintenance attributes that affect maintenance time; In maintainability assessments at each stage, identifying the maintenance attributes that affect maintenance time is a crucial foundation for predicting maintainability indicators and analyzing equipment maintainability. This invention identifies six dimensions of maintenance attributes affecting maintenance time: error-proofing maintenance attributes, visibility maintenance attributes, human factors engineering maintenance attributes, maintenance safety maintenance attributes, disassembly / reassembly maintenance attributes, and accessibility maintenance attributes. Their meanings and roles in the maintenance process are as follows: Error-proofing maintenance attributes refer to structural designs such as asymmetrical interfaces, pin positioning, different colored markings, or electronic interlocks that prevent maintenance personnel from continuing operations if parts are installed incorrectly, backwards, or omitted, thus physically eliminating human error. In other words, "only when installed correctly can it be installed." The evaluation of error-proofing maintenance attributes refers to the quality of the design's impact on maintenance time. For example, the impact on maintenance time could be achieved by eliminating rework time through the physical characteristic that "if it's wrong, it can't be installed."

[0032] Visual maintenance attributes refer to whether the equipment's status, fault points, operation markings, and maintenance areas can be directly and clearly seen by maintenance personnel. Good visibility includes transparent windows, level gauges, and clear status indicator lights, aiming to reduce "blind operation" and improve the efficiency of detection and diagnosis. The evaluation of visual maintenance attributes refers to the quality of the design that impacts maintenance time, such as allowing maintenance personnel to directly see the fault point, scale, or markings. This reduces the need to spend a lot of time removing obstructions to find the fault point or repeatedly checking the status with a flashlight, thus reducing search and confirmation time.

[0033] Human factors engineering maintenance attributes refer to whether maintenance work conforms to human physiological characteristics. This mainly considers factors such as whether the maintenance posture requires bending over or lying down, the amount of force exerted, the comfort of the operating space, and the adequacy of lighting, aiming to reduce maintenance worker fatigue and lower the risk of occupational injury. The evaluation of human factors engineering maintenance attributes refers to the quality of the design affecting maintenance time. For example, improper design, awkward positioning, excessive force, and easy fatigue of maintenance personnel can lead to slower movement speeds, even requiring intermittent rest, or causing distorted movements and reduced efficiency due to awkward operation. Avoiding fatigue and sluggish movements is crucial.

[0034] Maintenance safety attributes refer to the ability to ensure the safety of personnel, equipment, and the environment during maintenance. This includes preventing cuts from sharp edges, burns from high temperatures, and electric shocks, as well as the inclusion of prominent safety warning signs and power cut-off devices to ensure that the maintenance actions themselves do not pose a danger. The evaluation of maintenance safety attributes considers the quality of the design that impacts maintenance time. For example, poor maintenance safety due to the risk of sharp edges or high voltage necessitates that maintenance personnel wear heavy protective gear and operate with extreme caution and slow movements to avoid injury. A well-designed safety system allows maintenance personnel to perform faster operations with greater confidence and bolder actions, reducing search and confirmation time.

[0035] Disassembly and assembly maintenance attributes refer to the ease with which equipment components can be disassembled and assembled. This includes factors such as the use of standard tools, the uniformity of fastener types, the degree of modularity, and the complexity of disassembly and assembly steps, aiming to reduce disassembly and assembly time and the complexity of tool preparation. The evaluation of disassembly and assembly maintenance attributes refers to the quality of the design that impacts maintenance time. For example, disassembly and assembly is the most direct attribute affecting maintenance time. Good disassembly and assembly capabilities, such as the use of quick-release clips and a reduction in the number of fasteners, mean fewer turns of the screws and fewer tool changes. Poor disassembly and assembly capabilities mean a significant amount of time is wasted on repeatedly tightening screws and changing wrenches, directly reducing the time spent on tightening and loosening.

[0036] Accessibility maintenance attributes refer to the ease with which maintenance personnel can reach the part being repaired using their hands, tools, and line of sight. In other words, "able to reach and access." If the part being repaired is obstructed by other components or located deep within the equipment and difficult to reach, it is considered poor accessibility. The evaluation of accessibility maintenance attributes refers to the quality of the design that affects maintenance time; good accessibility means "easy to reach and touch." Poor accessibility means that maintenance personnel need to disassemble other normal components to reach the target, increasing auxiliary disassembly time, or because they cannot reach inside, they can only use extended tools to painstakingly operate bit by bit, resulting in extremely low efficiency in reducing the "reaching path" and auxiliary action time.

[0037] S22. Construct a five-language evaluation set and a seven-language evaluation set for evaluating six-dimensional maintenance attributes; The aforementioned six-dimensional maintenance attributes are often difficult to measure directly with precise numerical values, relying more on expert experience and qualitative judgment. Therefore, to improve the objectivity and consistency of the evaluation of these six-dimensional maintenance attributes, this invention introduces natural language value variables to describe and quantify the maintenance attributes. This method can better handle the ambiguity and subjectivity in the evaluation process, and is particularly suitable for attributes that are difficult to quantify precisely, such as error prevention, visibility, and maintenance safety.

[0038] This invention categorizes maintenance attributes into two types for evaluation based on the sensitivity of each attribute to its impact on maintenance time and the level of detail required for evaluation: For attributes that have a significant impact, such as error prevention, visibility, human factors engineering, maintenance safety, and maintenance time, a five-language evaluation set is used, namely: Vs={Excellent, Good, Average, Poor, Poor}.

[0039] For attributes such as disassembly and accessibility, which have a more subtle impact on the disassembly and assembly process, a seven-language evaluation set is used, namely: VT={Very good, Good, Fairly good, Average, Fairly poor, Poor, Very poor}.

[0040] S23. Construct a mapping relationship between the evaluation set and the evaluation values, transform the qualitative evaluation into quantitative values, and determine the basic maintenance action time correction coefficient corresponding to the evaluation values.

[0041] The evaluation set is quantified to transform qualitative evaluations into quantitative values, and a mapping relationship between the evaluation set and the evaluation values ​​is constructed.

[0042] Specifically, the relationship between the five-language evaluation set, the evaluation values, and the correction coefficient for basic maintenance action time is shown in Table 2 below: Table 2. Correspondence between the five language evaluation sets, evaluation values, and correction coefficients for basic maintenance action time. Furthermore, the relationship between the seven-language evaluation set, evaluation values, and the correction coefficient for basic maintenance action time is shown in Table 3 below: Table 3. Correspondence between the seven language evaluation sets, evaluation values, and correction coefficients for basic maintenance action time. S24. For each basic maintenance action obtained, perform a six-dimensional maintenance attribute evaluation based on the language evaluation set to obtain the set S of six-dimensional maintenance time correction coefficients corresponding to each basic maintenance action. The specific steps include: S241. Perform a six-dimensional maintenance attribute evaluation based on a language evaluation set for each basic maintenance action of the obtained lubricating oil temperature sensor maintenance task.

[0043] The following diagrams illustrate the process of evaluating six-dimensional maintenance attributes: Error-proofing maintenance attribute evaluation: The lubricating oil temperature sensor uses a threaded housing seal, has only one electrical connector plug, and no pipe joints. The evaluation considers the error-proofing design to be "Excellent" in natural language, ranking at Level 1 in its applicable five-language evaluation set, with a corresponding basic maintenance action time correction factor of K. E =k1=0.

[0044] Visibility maintenance attribute evaluation: The lubricating oil temperature sensor is installed on the upper part of the engine. Considering its installation on a helicopter, maintenance personnel can only stand on the side of the engine, resulting in moderate visibility. The visibility analysis using ergonomic simulation software (such as JACK) evaluates the visibility design as "good" in natural language, placing it at level 2 in its applicable five-language evaluation set. The corresponding basic maintenance action time correction factor is K. V =k2=0.25.

[0045] Human Factors Engineering Maintenance Attribute Evaluation: When maintenance personnel can only stand on the side of the engine for disassembly and assembly, they need to extend their arms. Using ergonomics simulation software (such as JACK's RULA function), the ergonomics analysis results indicate that the ergonomics design is rated as "Medium" in natural language, at level 3 of its applicable five-language evaluation set, with a corresponding basic maintenance action time correction factor of K. H =k3=0.5.

[0046] Maintenance safety and maintenance attribute evaluation: The sensing part of the lubricating oil temperature sensor is placed in lubricating oil. A small amount of oil will leak out during disassembly. Used lubricating oil is harmful to the human body. The evaluation considers the maintenance safety design to be "poor" in natural language, at level 4 of its applicable five-language evaluation set, with a corresponding basic maintenance action time correction factor of K. S =k4=0.75.

[0047] Disassembly and Repairability Evaluation: Disassembly is performed using an open-end wrench, and the repair space is good. The evaluation assigns a "good" rating to the disassembly and repairability design in natural language, placing it at Level 2 of the applicable seven-language evaluation set. The corresponding basic repair action time correction factor is K. R =K2=1 / 6.

[0048] Accessibility maintenance attribute evaluation: In the action of sealing the electrical connector plug, the results were analyzed using human factors engineering simulation software (e.g., JACK). The accessibility was very good, and the evaluation rated the accessibility design as "very good" in natural language, placing it at level 1 in its applicable seven-language evaluation set. The corresponding basic maintenance action time correction factor is K. A =K1=0.

[0049] Human-machine engineering simulation software (such as JACK) uses "digital humans" to "rehearse" on "digital engines" and is a tool for quantitatively evaluating maintenance attributes.

[0050] Each basic maintenance action was evaluated using a six-dimensional maintenance attribute based on a language evaluation set. The maintenance attribute analysis results, combined with the above findings, are shown in Table 4 below. Table 4: Quantitative Table of Repair Attributes Analysis for Lubricating Oil Temperature Sensor S242. Based on the six-dimensional maintenance attribute evaluation of each basic maintenance action, obtain the set S of six-dimensional maintenance time correction coefficients corresponding to each basic maintenance action: S=(K E K V K H K S K R K A ); Where, K E To consider the error-proofing maintenance attribute, the basic maintenance action time correction factor, K V A correction factor for the basic maintenance action time considering the visibility maintenance attribute; K H A correction factor for basic maintenance action time considering human factors engineering maintenance attributes; K S A basic maintenance action time correction factor, K, is used to consider maintenance safety and maintenance attributes. R A correction factor for the basic maintenance action time considering the disassembly and assembly maintenance attributes; K A The basic maintenance action time correction factor is used to take into account the accessibility maintenance attribute.

[0051] S3. Based on the simulation of the maintenance process model of turboshaft engine accessories, the maintenance time of multiple basic maintenance actions is determined by using a time measurement method (such as the MTM-1 method). The maintenance time of each basic maintenance action is corrected by the constructed maintenance time correction model and the six-dimensional time correction coefficient set S, so as to obtain the maintenance time after correction of the basic maintenance action.

[0052] The maintenance time correction model is as follows: T= N MTM ×0.036s×(1+(K E +K V +K H +K S +K R +K A ) / 6 ) ; Where T is the maintenance time after correction of the basic maintenance action, and N is the maintenance time after correction of the basic maintenance action. MTM This represents the number of basic time units required to complete a basic maintenance action, calculated using the MTM-1 analysis method.

[0053] MTM-1 is the most fundamental and precise system within the MTM methodology. Based on the simulation of the turboshaft engine accessory maintenance process model and the Pre-determined Time Standard Method (MTM-1) for maintenance work units, the disassembly and installation process of the lubricating oil temperature sensor was decomposed into motions and time measurements were performed. The turboshaft engine accessory maintenance process model simulation and the MTM-1 method are existing technologies for those skilled in the art and will not be elaborated upon here. The MTM-1 method fully considers basic motion elements such as posture transitions, eye movements, and precise operations, and determines the number N of basic time measurement units required to complete each basic maintenance action based on its standard time value card. MTM .

[0054] Based on this, and combining the maintenance time correction model and the six-dimensional time correction coefficient set S, the base time of each basic maintenance action is dynamically corrected. The correction coefficients are derived from the quantitative evaluation results of six attributes: error prevention, visibility, human factors engineering, maintenance safety, maintenance space, and accessibility. Each attribute correction coefficient is converted into a specific numerical value based on its linguistic score, and then comprehensively corrected to obtain the corrected maintenance time T for the basic maintenance action. T= N MTM ×0.036s×(1+(K E +K V +K H +K S +K R +K A ) / 6 ) ; Where, N MTM This represents the number of basic time units required to complete a basic maintenance action, calculated using the MTM-1 analysis method. Where 1+(K) E +K V +K H +K S +K R +K A The value of ) / 6 is the correction factor.

[0055] As shown in Table 4 above, the correction factor for the third basic maintenance action in the first maintenance work unit is: 1+(K E +K V +K H +K S +K R +K A ) / 6=1+(k1+k3+k3+k1+K1+K1) / 6=1+(0+0.5+0.5+0+0+0) / 6=1.17.

[0056] S4. Accumulate and calculate the corrected maintenance time for all basic maintenance actions in all maintenance work units to obtain the turboshaft engine accessory disassembly and assembly time based on maintenance process attributes. : ; Where i is the maintenance work unit number, i∈{1, 2, 3, ..., n}, n is the total number of maintenance work units obtained from the decomposition of the maintenance task; j is the basic maintenance action number, j∈{1, 2, 3, ..., m}. i},m i This represents the total number of basic maintenance actions in the i-th maintenance work unit obtained from the decomposition. The corrected maintenance time is the maintenance time for the j-th basic maintenance action in the i-th maintenance work unit.

[0057] For the maintenance task of the lubricating oil temperature sensor, there are two maintenance operation units: disassembling the lubricating oil temperature sensor and installing the lubricating oil temperature sensor, i∈{1,2}, that is, the total number of maintenance operation units n obtained from the maintenance task decomposition is 2. The lubricating oil temperature sensor disassembly maintenance operation unit is further subdivided into 7 basic maintenance actions, and the lubricating oil temperature sensor installation maintenance operation unit is further subdivided into 7 basic maintenance actions. That is, the total number of basic maintenance actions m1 in the first maintenance operation unit (disassembling the lubricating oil temperature sensor) is 7, and the total number of basic maintenance actions m2 in the second maintenance operation unit (disassembling the lubricating oil temperature sensor) is 7. Finally, the estimated time results of the lubricating oil temperature sensor disassembly and installation process are shown in Table 5 below.

[0058] Table 5: Expected timeline for the installation and removal of the lubricating oil temperature sensor As shown in the table above, the total time for disassembly was 156.45 seconds, the total time for installation was 132.94 seconds, and the estimated time for the overall disassembly and assembly task was 289.39 seconds. Testing showed that this result matches the actual maintenance time records in the project, indicating that the proposed time estimation method has high accuracy and engineering applicability.

[0059] Compared to traditional methods, this invention can more comprehensively reflect efficiency factors in actual maintenance scenarios, making it suitable for maintainability assessment and optimization during the design phase. It not only provides a reliable time prediction tool but also promotes a methodological shift in maintainability design from experience-driven to process modeling and quantitative evaluation, offering significant reference value for improving the economic efficiency and support effectiveness of turboshaft engine maintenance.

[0060] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for predicting the disassembly and assembly time of turboshaft engine accessories based on maintenance process attributes, characterized in that, It includes the following steps: S1. Combining the maintenance guidance information and time measurement method of turboshaft engine accessories, the maintenance task of turboshaft engine accessories is decomposed to obtain multiple maintenance work units and multiple basic maintenance actions in each maintenance work unit. S2. For each basic maintenance action obtained, a six-dimensional maintenance attribute evaluation based on the language evaluation set is performed to obtain the set of six-dimensional time correction coefficients S corresponding to each basic maintenance action: S=(K E ,K V ,K H ,K S ,K R ,K A ); Where, K E The basic maintenance action time correction factor considering error-proofing maintenance attributes; K V A correction factor for the basic maintenance action time considering the visibility maintenance attribute; K H A correction factor for basic maintenance action time considering human factors engineering maintenance attributes; K S A basic maintenance action time correction factor, K, is used to consider maintenance safety and maintenance attributes. R A correction factor for the basic maintenance action time considering the disassembly and assembly maintenance attributes; K A A basic maintenance action time correction factor that takes into account the accessibility maintenance attribute; S3. Based on the simulation of the maintenance process model of turboshaft engine accessories, the maintenance time of multiple basic maintenance actions is determined by the time measurement method. The maintenance time of each basic maintenance action is corrected by the constructed maintenance time correction model and the six-dimensional time correction coefficient set S, and the corrected maintenance time of the basic maintenance action is obtained. The maintenance time correction model is as follows: T= N MTM ×0.036s×(1+(K E +K V +K H +K S +K R +K A ) / 6 ) ; Where T is the maintenance time after correction of the basic maintenance action, and N is the maintenance time after correction of the basic maintenance action. MTM This refers to the number of basic time units required to complete a basic maintenance operation, calculated using time measurement methods. S4. Accumulate and calculate the corrected maintenance time for all basic maintenance actions in all maintenance work units to obtain the turboshaft engine accessory disassembly and assembly time based on maintenance process attributes. : ; Where i is the maintenance work unit number, i∈{1, 2, 3, ..., n}, n is the total number of maintenance work units obtained from the decomposition of the maintenance task; j is the basic maintenance action number, j∈{1, 2, 3, ..., m}. i },m i This represents the total number of basic maintenance actions in the i-th maintenance work unit obtained from the decomposition. The repair time is the adjusted repair time for the j-th basic repair action in the i-th repair work unit.

2. The method for predicting the disassembly and assembly time of turboshaft engine accessories based on maintenance process attributes according to claim 1, characterized in that, The six-dimensional maintenance attributes in S2 include error prevention maintenance attributes, visibility maintenance attributes, human factors engineering maintenance attributes, maintenance safety maintenance attributes, disassembly and assembly maintenance attributes, and accessibility maintenance attributes.

3. The method for predicting the disassembly and assembly time of turboshaft engine accessories based on maintenance process attributes according to claim 1, characterized in that, The language evaluation set in S2 includes a five-level language evaluation set Vs and a seven-level language evaluation set VT, where Vs = {excellent, good, average, poor, poor}; VT = {very good, good, fairly good, average, poor, poor, very poor}.

4. The method for predicting the disassembly and assembly time of turboshaft engine accessories based on maintenance process attributes according to claim 3, characterized in that, In S2, the error-proofing maintenance attribute, visibility maintenance attribute, human factors maintenance attribute, and maintenance safety maintenance attribute that significantly affect maintenance time are evaluated using a five-language evaluation set.

5. The method for predicting the disassembly and assembly time of turboshaft engine accessories based on maintenance process attributes according to claim 3, characterized in that, The evaluation of disassembly and accessibility maintenance attributes, which have a minor impact on the disassembly and assembly process, in S2 uses a seven-language evaluation set.

6. The method for predicting the disassembly and assembly time of turboshaft engine accessories based on maintenance process attributes according to claim 1, characterized in that, S1 specifically includes the following steps: S11. Obtain the disassembly and assembly procedures for turboshaft engine accessories based on the maintenance guide information for turboshaft engine accessories; S12. Combining the obtained disassembly and assembly procedures and time measurement methods, the maintenance tasks of the turboshaft engine accessories are decomposed to obtain multiple maintenance work units and multiple basic maintenance actions in each maintenance work unit.

7. The method for predicting the disassembly and assembly time of turboshaft engine accessories based on maintenance process attributes according to claim 1, characterized in that, S2 specifically includes the following steps: S21. Determine the six-dimensional maintenance attributes that affect maintenance time; S22. Construct a five-language evaluation set and a seven-language evaluation set for evaluating six-dimensional maintenance attributes; S23. Construct a mapping relationship between the evaluation set and the evaluation values, transform the qualitative evaluation into quantitative values, and determine the basic maintenance action time correction coefficient corresponding to the evaluation values. S24. For each basic maintenance action obtained, perform a six-dimensional maintenance attribute evaluation based on the language evaluation set to obtain the set of six-dimensional maintenance time correction coefficients S corresponding to each basic maintenance action: S=(K E ,K V ,K H ,K S ,K R ,K A ); Where, K E The basic maintenance action time correction factor considering error-proofing maintenance attributes; K V A correction factor for the basic maintenance action time considering the visibility maintenance attribute; K H A correction factor for basic maintenance action time considering human factors engineering maintenance attributes; K S A basic maintenance action time correction factor, K, is used to consider maintenance safety and maintenance attributes. R A correction factor for the basic maintenance action time considering the disassembly and assembly maintenance attributes; K A The basic maintenance action time correction factor is used to take into account the accessibility maintenance attribute.

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