Automatic air conditioner shell product quality detection method

Abstract

The invention relates to the technical field of product quality detection, in particular to an automatic air conditioner shell product quality detection method. The method comprises the following steps that the temperature, humidity and external stress of an air conditioner shell are collected and preprocessed; calculating the thermoelastic coupling stress of the air conditioner shell, constructing the oxidation acceleration influence of the air conditioner shell by using an activation energy model in combination with a thermal expansion coefficient, and analyzing and evaluating the durability safety of the air conditioner shell; based on the external stress, a multi-order random vibration equation is established by using Ito calculus, a time-varying stress field model is constructed to simulate an external dynamic load, and the strength grade of the air conditioner shell is evaluated in combination with the yield stress of the material; and comprehensively judging whether the quality of the air conditioner shell reaches the standard or not based on the durability safety and strength grade of the air conditioner shell. According to the automatic air conditioner shell product quality detection method, the quality of an air conditioner shell under different environmental conditions can be detected and evaluated through a time-varying stress field model based on multi-scale thermal and elastic coupling in combination with an activation energy model.

Description

Technical Field

[0001] The invention relates to the technical field of product quality detection, and in particular to a method for detecting the quality of an automatic air-conditioning shell product. Background Art

[0002] The automated air-conditioning casing product quality inspection method aims to accurately evaluate the durability and strength grade of the air-conditioning casing. By combining the multi-scale thermal-elastic coupling model with the random vibration extreme stress distribution model, the quality and safety of the air-conditioning casing under complex environmental conditions and dynamic loads can be controlled, and efficient, accurate and comprehensive automated quality inspection can be achieved to ensure the reliability and safety of the product in long-term use.

[0003] Existing air-conditioning casing product quality inspection methods usually find it difficult to simultaneously consider the nonlinear effects of temperature and humidity changes on material stress and the extreme stress distribution under dynamic loads. Since air-conditioning casings are often exposed to variable temperature and humidity conditions, and in actual applications, air-conditioning casings not only bear static loads, but also various dynamic loads, such as vibration during transportation, impact during operation, and wind changes in the environment, the durability of the air-conditioning casing may be unstable and even the safety may be greatly reduced. Therefore, an automated air-conditioning casing product quality inspection method is provided. Summary of the invention

[0004] The purpose of the present invention is to provide an automated air-conditioning casing product quality inspection method to solve the problem raised in the above background technology that the air-conditioning casing is often exposed to changing temperature and humidity conditions, and in actual applications, the air-conditioning casing not only bears static loads but also various dynamic loads, such as vibration during transportation, impact during operation, and changes in wind force in the environment, which may lead to unstable durability quality of the air-conditioning casing and even greatly reduced safety.

[0005] To achieve the above object, the present invention provides an automated air conditioner housing product quality detection method, comprising the following steps: S1, collecting and preprocessing the temperature, humidity and external stress of the air conditioner casing; S2. Based on temperature and humidity, the thermoelastic coupling stress of the air conditioner shell is calculated, and the activation energy model is used in combination with the thermal expansion coefficient to construct the oxidation acceleration effect of the air conditioner shell, and the durability and safety of the air conditioner shell are analyzed and evaluated; S3. Based on external stress, Ito calculus is used to establish multi-order random vibration equations, combined with the maximum stress distribution function, to construct a time-varying stress field model to simulate external dynamic loads, and combined with the material yield stress to evaluate the strength grade of the air conditioner shell; S4. Based on the durability, safety and strength level of the air-conditioning shell, comprehensively judge whether the quality of the air-conditioning shell meets the standards.

[0006] As a further improvement of the technical solution, in S1, the temperature, humidity, external stress and crack position data of the air conditioner casing are collected and preprocessed, and the specific method steps are as follows: S1.1. Use temperature and humidity sensors to collect the temperature around the air conditioner casing and humidity ; S1.2. Use stress sensors to collect external stress at the stress-bearing parts of the air conditioner casing ; S1.3. Clean the temperature, humidity and external stress data.

[0007] As a further improvement of the present technical solution, in S2, the thermoelastic coupling stress of the air conditioner housing is calculated based on temperature and humidity, and the activation energy model is used in combination with the thermal expansion coefficient to construct the oxidation acceleration effect of the air conditioner housing, and the durability and safety of the air conditioner housing are analyzed and evaluated. The specific method steps are as follows: S2.1. Couple the thermal stress and elastic stress of the air conditioner shell caused by temperature and humidity changes, and calculate the thermal-elastic coupling stress of the air conditioner shell; S2.2. Based on the activation energy model, the oxidation reaction rate of the air conditioner shell is simulated and calculated, and combined with the thermoelastic coupling stress, a strength attenuation model of the air conditioner shell over time is constructed, and the total stress on the air conditioner shell is calculated; S2.3. Based on the thermal stress, elastic stress coupling, oxidation reaction rate and total stress of the air-conditioning shell, a multi-scale temperature and humidity stress coupling model is constructed to evaluate the durability and safety of the air-conditioning shell.

[0008] As a further improvement of the technical solution, the S2.1, coupling the thermal stress and elastic stress of the air conditioner shell caused by the temperature and humidity changes, and calculating the thermal elastic coupling stress of the air conditioner shell, the specific method steps are as follows: S2.1.1. Based on the temperature change, the thermal stress is calculated using the thermal expansion coefficient of temperature and humidity and the Young's modulus of the material temperature and humidity: ; in, is the temperature and humidity dependent thermal expansion coefficient; is the temperature-dependent Young’s modulus; for temperature changes; is the nonlinear temperature index; for thermal stress; S2.1.2. Based on the humidity change, calculate the elastic stress using the humidity sensitivity coefficient and the Young's modulus of the material at temperature and humidity: ; in, is the humidity sensitivity coefficient dependent on temperature and humidity; For humidity changes; is a nonlinear humidity index; is the elastic stress; S2.1.3. Couple the thermal stress and elastic stress to calculate the thermal-elastic coupling stress of the air conditioner casing: ; in, is the thermoelastic coupling stress.

[0009] As a further improvement of the present technical solution, the S2.2, based on the activation energy model, simulates and calculates the oxidation reaction rate of the air-conditioning shell, and combines the thermoelastic coupling stress to construct a strength attenuation model of the air-conditioning shell over time, and calculates the total stress on the air-conditioning shell. The specific method steps are as follows: S2.2.1. Simulate and calculate the oxidation reaction rate of the air conditioner casing based on the activation energy model: ; in, It is the pre-oxidation factor; is the activation energy; is the Boltzmann constant; is the humidity impact index; is the oxidation reaction rate; S2.2.2. Combined with the thermoelastic coupling stress, a strength attenuation model of the air conditioner shell over time is constructed: ; in, is the strength decay model over time; is the initial material strength; is the yield strength; For time; is the integration variable; S2.2.3. Calculate the total stress on the air conditioner casing: ; in, For time The total stress below.

[0010] As a further improvement of the technical solution, S2.3, based on the thermal stress, elastic stress coupling, oxidation reaction rate and total stress of the air-conditioning shell, constructs a multi-scale temperature and humidity stress coupling model, and evaluates the durability and safety of the air-conditioning shell. The specific method steps are as follows: S2.3.1. Based on the thermal stress, elastic stress coupling, oxidation reaction rate and total stress of the air conditioner shell, a multi-scale temperature and humidity stress coupling model is constructed: ; in, is the time rate of change of total stress; is the time rate of change of thermal stress; is the time rate of change of elastic stress; is the oxidation reaction influence coefficient; Transfer operator for macro scale; S2.3.2. Solve the multi-scale temperature, humidity and stress coupling model to obtain the time Lower total stress And compare it with the material fatigue limit to evaluate the durability and safety of the air conditioner shell: ; in, is the material fatigue limit; To provide durable safety assessment results; It indicates that the durability of air conditioning materials is within a safe range at time t; It means that the durability of air conditioning materials is in an unsafe range at time t.

[0011] As a further improvement of the technical solution, in S3, based on external stress, Ito calculus is used to establish a multi-order random vibration equation, combined with the maximum stress distribution function, a time-varying stress field model is constructed to simulate the external dynamic load, and the strength grade of the air conditioner shell is evaluated in combination with the material yield stress; S3.1. Preliminary calculation of external dynamic load function based on external stress, and establishment of multi-order random vibration equations using Ito calculus to characterize the stress field of the air conditioner casing; S3.2, introduce a multi-scale coupling mechanism to combine the macroscopic stress response with the microscopic structural change, and adjust the attenuation and diffusion terms in the multi-order random vibration equation through the fractal dimension and time scale function; S3.3. Use the generalized extreme value distribution to construct the maximum stress distribution function of the air conditioner shell, and solve the ultimate stress of the air conditioner shell; S3.4. Based on the multi-order random vibration model and ultimate stress, a time-varying stress field model is constructed, and combined with the material yield stress, the strength grade of the air-conditioning casing is evaluated.

[0012] As a further improvement of the technical solution, in S3.1, the external dynamic load function is preliminarily calculated based on the external stress, and the multi-order random vibration equation is established using Ito calculus to characterize the stress field of the air conditioner casing. The specific method steps are as follows: S3.1.1. Preliminary calculation of external dynamic load function based on external stress: ; ; ; ; in, is the static load of external stress; It is a random vibration load; For periodic load; is the vibration amplitude coefficient; It is a standard Brownian motion process; is the amplitude; is the angular frequency; is the initial phase; is the external dynamic load function; S3.1.2. Based on the external dynamic load function, use Ito calculus to establish multi-order random vibration equations: Multi-order random vibration equations: ; in, is the stress field vector; is the attenuation matrix; is the diffusion matrix; is the Brownian motion vector; is the load coupling matrix; In S3.2, a multi-scale coupling mechanism is introduced to combine the macroscopic stress response with the microscopic structural change, and the attenuation and diffusion terms in the multi-order random vibration equation are adjusted through the fractal dimension and time scale function, as follows: ; ; in, is the fractal dimension; is a function of time scale; is the basic attenuation matrix; is the basic diffusion matrix.

[0013] As a further improvement of the present technical solution, in S3.3, the maximum stress distribution function of the stress on the air conditioner housing is constructed using the generalized extreme value distribution to solve the limit stress on the air conditioner housing. The specific method steps are as follows: S3.3.1. Use the generalized extreme value distribution to construct the maximum stress distribution function of the air conditioner casing: ; in, is the center position of the stress field; is the degree of dispersion of the stress field; is the shape parameter; is the maximum stress distribution function; S3.3.2. Based on the maximum stress distribution function, derive the ultimate stress of the stress field: ; in, is the confidence level; is the ultimate stress; In S3.4, based on the multi-order random vibration model and the ultimate stress, a time-varying stress field model is constructed, and combined with the material yield stress, the strength grade of the air conditioner casing is evaluated. The specific method steps are as follows: S3.4.1. Combine the multi-order random vibration model and the ultimate stress to construct a time-varying stress field model: ; in, is a time-varying stress field model; S3.4.2. Based on the time-varying stress field model And material yield stress, evaluate the strength grade of the air conditioner casing: ; in, is the material yield stress; is the material fracture stress; The results of the strength level assessment are: It means that the registered strength of the air conditioner shell at that time is the first-level safety level; It means that the registered strength of the air conditioner shell at that time is the second-level safer level; It means that the registered strength of the air conditioner casing at that time is level three unsafe level.

[0014] As a further improvement of the technical solution, in S4, based on the durability, safety and strength level of the air conditioner shell, a comprehensive judgment is made as to whether the quality of the air conditioner shell meets the standards, as follows: like and , the quality of air conditioner shell meets the standards; like and , the quality of the air conditioner casing barely meets the standards; like and , the quality of the air conditioner casing does not meet the standards; like , the quality of the air conditioner casing does not meet the standards.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. In this automated air-conditioning shell product quality inspection method, based on the multi-scale thermoelastic coupling and oxidation acceleration impact model, the durability and safety of the air-conditioning shell under different environmental conditions can be accurately evaluated.

[0016] 2. In the automated air-conditioning shell product quality inspection method, the strength grade of the air-conditioning shell under dynamic load is evaluated through the random vibration theory and the time-varying stress field modeling of the extreme stress distribution model. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure is a flow chart of the overall method of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Example: See also Figure 1 As shown, this embodiment provides an automated air conditioner housing product quality detection method, comprising the following steps: S1, collecting and preprocessing the temperature, humidity and external stress of the air conditioner casing; In this embodiment S1, the temperature, humidity, external stress and crack position data of the air conditioner casing are collected and preprocessed, and the specific method steps are as follows: S1.1. Use temperature and humidity sensors to collect the temperature around the air conditioner casing and humidity ; S1.2. Use stress sensors to collect external stress at the stress-bearing parts of the air conditioner casing ; S1.3. Clean the temperature, humidity and external stress data.

[0020] S2. Based on temperature and humidity, the thermoelastic coupling stress of the air conditioner shell is calculated, and the activation energy model is used in combination with the thermal expansion coefficient to construct the oxidation acceleration effect of the air conditioner shell, and the durability and safety of the air conditioner shell are analyzed and evaluated; In this embodiment, the activation energy model is used to describe the kinetic model of the oxidation reaction rate of the material under different temperature and humidity conditions. By calculating the energy barrier required for the oxidation reaction, the dynamic response of the oxidation rate with environmental changes is predicted. The activation energy model is used in combination with the thermal expansion coefficient to construct the oxidation acceleration effect of the air-conditioning shell. The analysis and evaluation of the durability and safety of the air-conditioning shell is to simulate the effect of temperature and humidity changes on the oxidation rate of the material, quantify the attenuation of the oxidation reaction on the material strength, and thus accurately evaluate the durability and safety of the air-conditioning shell in long-term use. The thermal expansion coefficient describes the expansion behavior of materials under temperature changes. By combining the activation energy model with the thermal expansion coefficient, the comprehensive impact of temperature and humidity changes on materials can be more comprehensively simulated. Specifically, temperature and humidity changes not only directly affect the thermoelastic coupling stress of materials, but also further accelerate the oxidation reaction by changing the expansion behavior of materials. This coupling effect significantly increases the oxidation rate of materials in stress concentration areas, resulting in faster attenuation of material strength. In this embodiment S2, based on temperature and humidity, the thermoelastic coupling stress of the air conditioner housing is calculated, and the activation energy model is used in combination with the thermal expansion coefficient to construct the oxidation acceleration effect of the air conditioner housing, and the durability and safety of the air conditioner housing are analyzed and evaluated. The specific method steps are as follows: S2.1. Couple the thermal stress and elastic stress of the air conditioner shell caused by temperature and humidity changes, and calculate the thermal-elastic coupling stress of the air conditioner shell; S2.2. Based on the activation energy model, the oxidation reaction rate of the air conditioner shell is simulated and calculated, and combined with the thermoelastic coupling stress, a strength attenuation model of the air conditioner shell over time is constructed, and the total stress on the air conditioner shell is calculated; S2.3. Based on the thermal stress, elastic stress coupling, oxidation reaction rate and total stress of the air-conditioning shell, a multi-scale temperature and humidity stress coupling model is constructed to evaluate the durability and safety of the air-conditioning shell.

[0021] In this embodiment S2.1, the thermal stress and elastic stress of the air conditioner housing are coupled by the temperature and humidity changes, and the thermal elastic coupling stress of the air conditioner housing is calculated. The specific method steps are as follows: S2.1.1. Based on the temperature change, the thermal stress is calculated using the thermal expansion coefficient of temperature and humidity and the Young's modulus of the material temperature and humidity: ; in, is the temperature and humidity dependent thermal expansion coefficient; is the temperature-dependent Young’s modulus; for temperature changes; is the nonlinear temperature index; for thermal stress; S2.1.2. Based on the humidity change, calculate the elastic stress using the humidity sensitivity coefficient and the Young's modulus of the material at temperature and humidity: ; in, is the humidity sensitivity coefficient dependent on temperature and humidity; For humidity changes; is a nonlinear humidity index; is the elastic stress; S2.1.3. Couple the thermal stress and elastic stress to calculate the thermal-elastic coupling stress of the air conditioner casing: ; in, is the thermoelastic coupling stress.

[0022] In this embodiment S2.2, the oxidation reaction rate of the air conditioner casing is simulated and calculated based on the activation energy model, and the strength attenuation model of the air conditioner casing over time is constructed in combination with the thermoelastic coupling stress, and the total stress on the air conditioner casing is calculated. The specific method steps are as follows: S2.2.1. Simulate and calculate the oxidation reaction rate of the air conditioner casing based on the activation energy model: ; in, It is the pre-oxidation factor; is the activation energy; is the Boltzmann constant; is the humidity impact index; is the oxidation reaction rate; S2.2.2. Combined with the thermoelastic coupling stress, a strength attenuation model of the air conditioner shell over time is constructed: ; in, is the strength decay model over time; is the initial material strength; is the yield strength; For time; is the integration variable; S2.2.3. Calculate the total stress on the air conditioner casing: ; in, For time The total stress below.

[0023] In this embodiment S2.3, based on the thermal stress, elastic stress coupling, oxidation reaction rate and total stress of the air conditioner shell, a multi-scale temperature and humidity stress coupling model is constructed, and the durability and safety of the air conditioner shell is evaluated. The specific method steps are as follows: S2.3.1. Based on the thermal stress, elastic stress coupling, oxidation reaction rate and total stress of the air conditioner shell, a multi-scale temperature and humidity stress coupling model is constructed: ; in, is the time rate of change of total stress; is the time rate of change of thermal stress; is the time rate of change of elastic stress; is the oxidation reaction influence coefficient; Transfer operator for macro scale; S2.3.2. Solve the multi-scale temperature, humidity and stress coupling model to obtain the time Lower total stress And compare it with the material fatigue limit to evaluate the durability and safety of the air conditioner shell: ; in, is the material fatigue limit; To provide durable safety assessment results; It indicates that the durability of air conditioning materials is within a safe range at time t; It means that the durability of air conditioning materials is in an unsafe range at time t.

[0024] S3. Based on external stress, Ito calculus is used to establish multi-order random vibration equations, combined with the maximum stress distribution function, to construct a time-varying stress field model to simulate external dynamic loads, and combined with the material yield stress to evaluate the strength grade of the air conditioner shell; In this embodiment, Ito calculus is a mathematical tool for analyzing and solving random processes, and is particularly suitable for processing differential equations containing random noise. In S3, Ito calculus is used to establish a multi-order random vibration equation that describes the stress field changes of the air conditioner shell under external dynamic loads; Multi-order random vibration equations are a class of high-order or multi-dimensional stochastic differential equations used to describe the response of a system under a variety of random external dynamic loads. Multi-order random vibration equations are used to model the stress field changes of air conditioner casings under complex dynamic loads. The time-varying stress field model refers to a stress field description model that can dynamically change with time. It is used to simulate the stress distribution and evolution of the air-conditioning shell under external dynamic loads. The time-varying stress field model combines random vibration theory and extreme stress distribution function to comprehensively simulate and evaluate the strength level of the shell. In this embodiment S3, based on external stress, Ito calculus is used to establish multi-order random vibration equations, combined with the maximum stress distribution function, a time-varying stress field model is constructed to simulate external dynamic loads, and the strength grade of the air conditioner casing is evaluated in combination with the material yield stress; S3.1. Preliminary calculation of external dynamic load function based on external stress, and establishment of multi-order random vibration equations using Ito calculus to characterize the stress field of the air conditioner casing; S3.2, introduce a multi-scale coupling mechanism to combine the macroscopic stress response with the microscopic structural change, and adjust the attenuation and diffusion terms in the multi-order random vibration equation through the fractal dimension and time scale function; S3.3. Use the generalized extreme value distribution to construct the maximum stress distribution function of the air conditioner shell, and solve the ultimate stress of the air conditioner shell; S3.4. Based on the multi-order random vibration model and ultimate stress, a time-varying stress field model is constructed, and combined with the material yield stress, the strength grade of the air-conditioning casing is evaluated.

[0025] In this embodiment S3.1, the external dynamic load function is preliminarily calculated based on the external stress, and the multi-order random vibration equation is established using Ito calculus to characterize the stress field of the air conditioner housing. The specific method steps are as follows: S3.1.1. Preliminary calculation of external dynamic load function based on external stress: ; ; ; ; in, is the static load of external stress; It is a random vibration load; For periodic load; is the vibration amplitude coefficient; It is a standard Brownian motion process; is the amplitude; is the angular frequency; is the initial phase; is the external dynamic load function; In this embodiment S3.1.1, the external stress is the result of multiple factors, including wind force, vibration, mechanical operation, and temperature change. By modeling the effects of these factors, an external dynamic load function based on time changes can be obtained; External stress can be decomposed into static load, random vibration load and cyclic load; Static load is a constant stress caused by the mass of external equipment, gravity, etc. Static load is usually a constant; Random vibration loads are time-varying loads caused by external irregular vibrations or shocks, which can be modeled using white noise; Periodic loads are loads caused by periodic mechanical motion or environmental conditions, expressed in the form of sine waves or cosine waves, reflecting loads caused by periodic changes; S3.1.2. Based on the external dynamic load function, use Ito calculus to establish multi-order random vibration equations: Multi-order random vibration equations: ; in, is the stress field vector; is the attenuation matrix; is the diffusion matrix; is the Brownian motion vector; is the load coupling matrix; In this embodiment S3.2, a multi-scale coupling mechanism is introduced to combine the macroscopic stress response with the microscopic structural change, and the attenuation and diffusion terms in the multi-order random vibration equation are adjusted through the fractal dimension and time scale function, as follows: ; ; in, is the fractal dimension; is a function of time scale; is the basic attenuation matrix; is the basic diffusion matrix.

[0026] In this embodiment S3.3, the maximum stress distribution function of the stress on the air conditioner housing is constructed using the generalized extreme value distribution to solve the limit stress on the air conditioner housing. The specific method steps are as follows: S3.3.1. Use the generalized extreme value distribution to construct the maximum stress distribution function of the air conditioner casing: ; in, is the center position of the stress field; is the degree of dispersion of the stress field; is the shape parameter; is the maximum stress distribution function; S3.3.2. Based on the maximum stress distribution function, derive the ultimate stress of the stress field: ; in, is the confidence level; is the ultimate stress; In this embodiment S3.4, based on the multi-order random vibration model and the limit stress, a time-varying stress field model is constructed, and combined with the material yield stress, the strength grade of the air conditioner casing is evaluated. The specific method steps are as follows: S3.4.1. Combine the multi-order random vibration model and the ultimate stress to construct a time-varying stress field model: ; in, is a time-varying stress field model; S3.4.2. Based on the time-varying stress field model And material yield stress, evaluate the strength grade of the air conditioner casing: ; in, is the material yield stress; is the material fracture stress; The results of the strength level assessment are: It means that the registered strength of the air conditioner shell at that time is the first-level safety level; It means that the registered strength of the air conditioner shell at that time is the second-level safer level; It means that the registered strength of the air conditioner casing at that time is level three unsafe level.

[0027] S4. Based on the durability, safety and strength level of the air conditioner shell, comprehensively judge whether the quality of the air conditioner shell meets the standards; In this embodiment S4, based on the durability, safety and strength level of the air conditioner casing, a comprehensive judgment is made as to whether the quality of the air conditioner casing meets the standards, as follows: like and , the quality of air conditioner shell meets the standards; like and , the quality of the air conditioner casing barely meets the standards; like and , the quality of the air conditioner casing does not meet the standards; like , the quality of the air conditioner casing does not meet the standards.

[0028] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only preferred examples of the present invention, and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. An automated air conditioner housing product quality inspection method, characterized in that: The following steps are involved: S1, collecting and preprocessing the temperature, humidity and external stress of the air conditioner casing; S2. Based on temperature and humidity, the thermoelastic coupling stress of the air conditioner shell is calculated, and the activation energy model is used in combination with the thermal expansion coefficient to construct the oxidation acceleration effect of the air conditioner shell, and the durability and safety of the air conditioner shell are analyzed and evaluated; S3. Based on external stress, Ito calculus is used to establish multi-order random vibration equations, combined with the maximum stress distribution function, to construct a time-varying stress field model to simulate external dynamic loads, and combined with the material yield stress to evaluate the strength grade of the air conditioner shell; S4. Based on the durability, safety and strength level of the air-conditioning shell, comprehensively judge whether the quality of the air-conditioning shell meets the standards.

2. The automatic air-conditioning shell product quality detection method according to claim 1 is characterized in that: In S1, the temperature, humidity, external stress and crack location data of the air conditioner casing are collected and preprocessed. The specific method steps are as follows: S1.

1. Use temperature and humidity sensors to collect the temperature around the air conditioner casing and humidity ; S1.

2. Use stress sensors to collect external stress at the stress-bearing parts of the air conditioner casing ; S1.

3. Clean the temperature, humidity and external stress data.

3. The method for detecting the quality of the automatic air-conditioning shell product according to claim 2 is characterized in that: In S2, based on temperature and humidity, the thermoelastic coupling stress of the air conditioner shell is calculated, and the oxidation acceleration effect of the air conditioner shell is constructed using the activation energy model combined with the thermal expansion coefficient to analyze and evaluate the durability and safety of the air conditioner shell. The specific method steps are as follows: S2.

1. Couple the thermal stress and elastic stress of the air conditioner shell caused by temperature and humidity changes, and calculate the thermal-elastic coupling stress of the air conditioner shell; S2.

2. Based on the activation energy model, the oxidation reaction rate of the air conditioner shell is simulated and calculated, and combined with the thermoelastic coupling stress, a strength attenuation model of the air conditioner shell over time is constructed, and the total stress on the air conditioner shell is calculated; S2.

3. Based on the thermal stress, elastic stress coupling, oxidation reaction rate and total stress of the air-conditioning shell, a multi-scale temperature and humidity stress coupling model is constructed to evaluate the durability and safety of the air-conditioning shell.

4. The method for detecting the quality of an automatic air-conditioning shell product according to claim 3 is characterized in that: S2.1, coupling the thermal stress and elastic stress of the air conditioner shell caused by temperature and humidity changes, and calculating the thermal elastic coupling stress of the air conditioner shell, the specific method steps are as follows: S2.1.

1. Based on the temperature change, the thermal stress is calculated using the thermal expansion coefficient of temperature and humidity and the Young's modulus of the material temperature and humidity: ； in, is the temperature and humidity dependent thermal expansion coefficient; is the temperature-dependent Young’s modulus; for temperature changes; is the nonlinear temperature index; for thermal stress; S2.1.

2. Based on the humidity change, calculate the elastic stress using the humidity sensitivity coefficient and the Young's modulus of the material temperature and humidity: ； in, is the humidity sensitivity coefficient dependent on temperature and humidity; For humidity changes; is a nonlinear humidity index; is the elastic stress; S2.1.

3. Couple the thermal stress and elastic stress to calculate the thermal-elastic coupling stress of the air conditioner casing: ； in, is the thermoelastic coupling stress.

5. The method for detecting the quality of the automatic air-conditioning shell product according to claim 4 is characterized in that: S2.2, based on the activation energy model, simulates and calculates the oxidation reaction rate of the air conditioner shell, and combines the thermoelastic coupling stress to construct a strength attenuation model of the air conditioner shell over time, and calculates the total stress on the air conditioner shell. The specific method steps are as follows: S2.2.

1. Simulate and calculate the oxidation reaction rate of the air conditioner casing based on the activation energy model: ； in, It is the pre-oxidation factor; is the activation energy; is the Boltzmann constant; is the humidity impact index; is the oxidation reaction rate; S2.2.

2. Combined with the thermoelastic coupling stress, a strength attenuation model of the air conditioner shell over time is constructed: ； in, is the strength decay model over time; is the initial material strength; is the yield strength; For time; is the integration variable; S2.2.

3. Calculate the total stress on the air conditioner casing: ； in, For time The total stress below.

6. The method for detecting the quality of an automatic air-conditioning shell product according to claim 5, characterized in that: S2.3, based on the thermal stress, elastic stress coupling, oxidation reaction rate and total stress of the air conditioner shell, a multi-scale temperature and humidity stress coupling model is constructed to evaluate the durability and safety of the air conditioner shell. The specific method steps are as follows: S2.3.

1. Based on the thermal stress, elastic stress coupling, oxidation reaction rate and total stress of the air conditioner shell, a multi-scale temperature and humidity stress coupling model is constructed: ； in, is the time rate of change of total stress; is the time rate of change of thermal stress; is the time rate of change of elastic stress; is the oxidation reaction influence coefficient; Transfer operator for macro scale; S2.3.

2. Solve the multi-scale temperature, humidity and stress coupling model to obtain the time Lower total stress And compare it with the material fatigue limit to evaluate the durability and safety of the air conditioner shell: ； in, is the material fatigue limit; To provide durable safety assessment results; It indicates that the durability of air conditioning materials is within a safe range at time t; It means that the durability of air conditioning materials is in an unsafe range at time t.

7. The method for detecting the quality of an automatic air-conditioning shell product according to claim 6, characterized in that: In S3, based on external stress, Ito calculus is used to establish multi-order random vibration equations, combined with the maximum stress distribution function, a time-varying stress field model is constructed to simulate external dynamic loads, and the strength grade of the air conditioner shell is evaluated in combination with the material yield stress; S3.

1. Preliminary calculation of external dynamic load function based on external stress, and establishment of multi-order random vibration equations using Ito calculus to characterize the stress field of the air conditioner casing; S3.2, introduce a multi-scale coupling mechanism to combine the macroscopic stress response with the microscopic structural change, and adjust the attenuation and diffusion terms in the multi-order random vibration equation through the fractal dimension and time scale function; S3.

3. Use the generalized extreme value distribution to construct the maximum stress distribution function of the air conditioner shell, and solve the ultimate stress of the air conditioner shell; S3.

4. Based on the multi-order random vibration model and ultimate stress, a time-varying stress field model is constructed, and combined with the material yield stress, the strength grade of the air-conditioning casing is evaluated.

8. The method for detecting the quality of the automatic air-conditioning shell product according to claim 7, characterized in that: In S3.1, the external dynamic load function is preliminarily calculated based on the external stress, and the multi-order random vibration equation is established using Ito calculus to characterize the stress field of the air conditioner shell. The specific method steps are as follows: S3.1.

1. Preliminary calculation of external dynamic load function based on external stress: ； ； ； ； in, is the static load of external stress; It is a random vibration load; For periodic load; is the vibration amplitude coefficient; It is a standard Brownian motion process; is the amplitude; is the angular frequency; is the initial phase; is the external dynamic load function; S3.1.

2. Based on the external dynamic load function, use Ito calculus to establish multi-order random vibration equations: Multi-order random vibration equations: ； in, is the stress field vector; is the attenuation matrix; is the diffusion matrix; is the Brownian motion vector; is the load coupling matrix; In S3.2, a multi-scale coupling mechanism is introduced to combine the macroscopic stress response with the microscopic structural change, and the attenuation and diffusion terms in the multi-order random vibration equation are adjusted through the fractal dimension and time scale function, as follows: ； ； in, is the fractal dimension; is a function of time scale; is the basic attenuation matrix; is the basic diffusion matrix.

9. The method for detecting the quality of an automatic air-conditioning shell product according to claim 8, characterized in that: In S3.3, the maximum stress distribution function of the stress on the air conditioner shell is constructed using the generalized extreme value distribution to solve the limit stress on the air conditioner shell. The specific method steps are as follows: S3.3.

1. Use the generalized extreme value distribution to construct the maximum stress distribution function of the air conditioner casing: ； in, is the center position of the stress field; is the degree of dispersion of the stress field; is the shape parameter; is the maximum stress distribution function; S3.3.

2. Based on the maximum stress distribution function, derive the ultimate stress of the stress field: ； in, is the confidence level; is the ultimate stress; In S3.4, based on the multi-order random vibration model and the ultimate stress, a time-varying stress field model is constructed, and combined with the material yield stress, the strength grade of the air conditioner casing is evaluated. The specific method steps are as follows: S3.4.

1. Combine the multi-order random vibration model and the ultimate stress to construct a time-varying stress field model: ； in, is a time-varying stress field model; S3.4.

2. Based on the time-varying stress field model And material yield stress, evaluate the strength grade of the air conditioner casing: ； in, is the material yield stress; is the material fracture stress; The results of the strength level assessment are: It means that the registered strength of the air conditioner shell at that time is the first-level safety level; It means that the registered strength of the air conditioner shell at that time is the second-level safer level; It means that the registered strength of the air conditioner casing at that time is level three unsafe level.

10. The automatic air-conditioning shell product quality detection method according to claim 9 is characterized in that: In S4, based on the durability, safety and strength level of the air conditioner casing, a comprehensive judgment is made as to whether the quality of the air conditioner casing meets the standards, as follows: like and , the quality of air conditioner shell meets the standards; like and , the quality of the air conditioner casing barely meets the standards; like and , the quality of the air conditioner casing does not meet the standards; like , the quality of the air conditioner casing does not meet the standards.

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