A quantitative calculation method for multi-mechanism heat generation efficiency of induction welding for orthogonal lay-up thermoplastic composites

Abstract

This invention relates to a quantitative calculation method for the heat generation efficiency of multiple mechanisms in induction welding of orthogonal lay-up thermoplastic composites, belonging to the field of thermoplastic composite structure forming technology. S1: Establish a heat generation model based on the material's microstructure; S2: Based on the heat generation model, establish a quantitative relationship between dielectric loss, contact resistance heating, and fiber heating; S3: Conduct induction welding experiments and DSC tests on two different materials to determine the heat generation; S4: Based on the model and measurement results, calculate the proportion and heat generation of different heat generation mechanisms in induction welding. This invention reveals the induction welding mechanism of orthogonal lay-up composite materials, enabling quantitative acquisition of the heat generation and proportion of multiple heat generation mechanisms in induction welding. This provides data support for achieving high-quality and efficient connections in thermoplastic composite structures and provides a theoretical basis for accurate prediction of interface temperatures in induction welding of composite materials with different lay-up forms.

Description

Technical Field

[0001] This invention relates to the field of thermoplastic composite material structure molding technology, and in particular to a quantitative calculation method for the multi-mechanism heat generation efficiency of induction welding of orthogonal lay-up thermoplastic composite materials. Background Technology

[0002] Thermoplastic composites are composite materials made using thermoplastic polymers such as polyethylene (PE), polyamide (PA), polyphenylene sulfide (PPS), polyetherimide (PEI), polyether ketone ketone (PEKK), and polyether ether ketone (PEEK) as the matrix and various continuous / discontinuous fibers such as carbon fiber, glass fiber, and aramid fiber as reinforcement. Orthogonal layup laminates are composite materials made by laying up unidirectional prepregs with fiber orientations of 0° and 90°.

[0003] In recent years, fiber-reinforced thermoplastic composites based on thermoplastic resins have developed rapidly and are an important branch of composite materials. Carbon fiber reinforced thermoplastic composites possess excellent properties such as high toughness, corrosion resistance, fatigue resistance, simple molding process with short cycle time, high production efficiency, high material utilization (no waste), remelting and molding capability, and weldability, and have been widely used in the automotive, aerospace, and other fields.

[0004] Induction welding offers advantages such as precise welding area, high flexibility, and non-contact welding. It avoids the stress concentration and weight increase problems of traditional mechanical connections, the incompatibility between adhesives and weakly polar thermoplastic resins and poor environmental adaptability in adhesive bonding, the stress concentration and electrochemical corrosion caused by resistance wire residue at the welding interface in resistance welding, and the limitations of ultrasonic welding, which is unsuitable for large-area or specially shaped structural components. Therefore, induction welding is considered one of the most promising technologies for joining thermoplastic composite materials.

[0005] However, the heat generation mechanisms in induction welding of orthogonal lay-up thermoplastic composites mainly include fiber heating, dielectric loss, and contact resistance heating. The multi-source nature of the heat generation mechanisms in the induction welding area poses a challenge to the uniform control of the temperature field at the welding interface, becoming a key issue restricting the further application of induction welding technology. Summary of the Invention

[0006] To address the problems existing in the background art, the present invention aims to provide a quantitative calculation method for the multi-mechanism heat generation efficiency in the induction welding process of orthogonal lay-up thermoplastic composite materials. By establishing quantitative relationships between various heat generation mechanisms in the induction welding process, the heat generation of different heat generation mechanisms is measured, and quantitative data on the proportion and heat generation of different heat generation mechanisms in induction welding are obtained through calculation, thereby solving the problems existing in the background art.

[0007] The present invention achieves the above-mentioned technical objectives by adopting the following technical solutions:

[0008] A quantitative calculation method for the multi-mechanism heat generation efficiency of induction welding of orthogonal lay-up thermoplastic composites includes the following steps:

[0009] S1: Based on the microstructure of orthogonal lay-up thermoplastic composites, a heat generation model is established;

[0010] S2: Based on the established heat generation model, analyze the quantitative relationship between dielectric loss, contact resistance heating and fiber heating in the heat generation mechanism;

[0011] S3: Design induction welding tests and DSC tests for two different materials in orthogonal lay-up thermoplastic composites, and determine the heat generation;

[0012] S4: Based on the heat generation model and the analysis and test results of steps S2 and S3, calculate the proportion and heat generation of different heat generation mechanisms in induction welding.

[0013] Based on the above scheme, a further preferred embodiment of the present invention is as follows: In step S1 above, the microstructure of the thermoplastic composite material is as follows:

[0014]

[0015] Among them, V f The volume fraction of the composite fiber is represented by 'a', the thickness of the prepreg is represented by 'd'. f Indicates the diameter of a single fiber bundle in the prepreg;

[0016] l f =a (2)

[0017] Among them, l f Indicates the fiber length in a microcircuit;

[0018]

[0019] Among them, A f Indicates the cross-sectional area of ​​the fiber;

[0020]

[0021] Among them, A j This indicates the cross-sectional area of ​​the resin matrix.

[0022] Based on the above scheme, a further preferred embodiment of the present invention is as follows: In step S1 above, establishing the heat generation model specifically includes the following steps:

[0023] S101: Fiber heating inside carbon fiber

[0024] p f=I f 2 R f (5)

[0025] Where, p f R represents the fiber heating power, I represents the fiber current in the circuit, and R represents the fiber heating power. f Indicates the electrical resistance of carbon fiber;

[0026] S102: Dielectric loss of the resin at the junction

[0027]

[0028] Where, p jd I represents dielectric loss power. jd R represents the dielectric loss current at the node. jd denoted by ε0, h represents the resin thickness, ω represents the power supply angular frequency, ε0 ​​represents the vacuum dielectric constant, k represents the dielectric constant of the resin matrix, and tanδ represents the delay angle of the resin matrix.

[0029] S103: Contact resistance heating at the junction

[0030] p jc =I jc 2 R jc (7)

[0031] Where, p jc I represents the contact resistance heating power. jc R represents the contact resistance current at the node. jc This indicates the contact resistance.

[0032] In induction welding of orthogonal lay-up thermoplastic composites, the quantitative relationship between the current in the fiber and the current at the junction is as follows:

[0033]

[0034] I f =I jc or I f =I jdt (9)

[0035] I jdt =I c +I jd (10)

[0036]

[0037] Among them, I c I represents the charging current at the dielectric loss junction. jdt This represents the total current at the dielectric loss junction.

[0038] Based on the above scheme, a further preferred embodiment of the present invention is as follows: In step S2 above, during induction welding of orthogonal lay-up thermoplastic composite materials, the quantitative relationship between dielectric loss and fiber heating is as follows:

[0039]

[0040] Where M represents the ratio of dielectric loss in the microcircuit to fiber heating.

[0041] Based on the above scheme, a further preferred embodiment of the present invention is as follows: In step S3 above, the quantitative relationship between contact resistance heating and fiber heating in the induction heating of orthogonal lay-up thermoplastic composite material is as follows:

[0042]

[0043] Where N represents the ratio of contact resistance heating to fiber heating in the microcircuit.

[0044] Based on the above scheme, a further preferred embodiment of the present invention is as follows: In step S2 above, the total resistance in the thickness direction of the composite material is as follows:

[0045]

[0046] Among them, R jt This represents the total resistance along the thickness direction of the composite material.

[0047] Based on the above scheme, a further preferred embodiment of the present invention is as follows: In step S4 above, the heat generation of the two different materials within the same time period is as follows:

[0048]

[0049] Where Q1 and Q2 represent the heat generation of composite material 1 and composite material 2, respectively; C1 and C2 represent the specific heat capacity of composite material 1 and composite material 2, respectively; m1 and m2 represent the mass of composite material 1 and composite material 2, respectively; and T represents the heat generation of composite material 1 and composite material 2, respectively. 0-1 T 0-2 and T 1-1 T 1-2 These represent the initial and final temperature values ​​of composite material 1 and composite material 2 during the induction welding test, respectively.

[0050] Based on the above scheme, a further preferred embodiment of the present invention is as follows: In step S5 above, the proportion and heat generation relationship of the different heat generation mechanisms of the two different materials induction welding are as follows:

[0051]

[0052] Where M1 and M2 represent the ratio of dielectric loss to fiber heating in composite material 1 and composite material 2, respectively; N1 and N2 represent the ratio of contact resistance heating to fiber heating in composite material 1 and composite material 2, respectively; m and n represent the ratio of dielectric loss to contact resistance heating, respectively; and P... f1 and P f2 R represents the amount of heat generated by heating the fibers of composite material 1 and composite material 2, respectively. jt1 R jt2 These represent the contact resistances of composite material 1 and composite material 2, respectively.

[0053] By adopting the above-described technical solution, the present invention has the following beneficial technical effects compared with the prior art:

[0054] 1. By establishing a heat generation model for orthogonal layup thermoplastic composites in induction welding, and combining the evolution law of the inherent electrical and thermal properties of composites, quantitative calculation methods were established for different heat generation efficiencies of dielectric loss and fiber heating, and contact resistance heating and fiber heating in induction welding. Induction welding experiments and DSC tests of different orthogonal layup thermoplastic composites were designed to obtain the proportion and heat generation of different heat generation mechanisms in induction welding, revealing the induction welding mechanism of orthogonal layup composites, and providing a theoretical basis for accurate prediction of interface temperature in induction welding of composites with different layup forms.

[0055] 2. The quantitative calculation method proposed in this invention for the heat generation efficiency of orthogonal lay-up thermoplastic composites in induction welding using different mechanisms can explore the quantitative ratios between different heat generation mechanisms in the induction welding of composite materials. Calculations show that the proportions of dielectric loss and contact resistance heating at the joints of [0 / 90 / 0 / 90]CF / PEEK and CF / PPS composite laminates are m = 0.1147 and n = 0.8853, respectively, and the ratios of heat generation from dielectric loss and contact resistance heating are mgM. PEEK ngN PEEK =2.0192 and mgM PPS ngN PPS =4.7294, which shows that dielectric loss is the dominant heat generation mechanism at the junction. At the same time, the heat generation ratio of dielectric loss in the two composite materials was calculated to be 0.6688 and 0.8255, respectively. Attached Figure Description

[0056] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below.

[0057] Figure 1 This is an overall flowchart of a quantitative calculation method for the multi-mechanism heat generation efficiency of induction welding of orthogonal lay-up thermoplastic composite materials according to the present invention.

[0058] Figure 2 This is a typical microstructure of the thermoplastic composite unidirectional prepreg of the present invention.

[0059] Figure 3 This is a schematic diagram of the circuit micro-unit in the induction welding of orthogonal lay-up thermoplastic composite materials according to the present invention.

[0060] Figure 4 This is an equivalent circuit diagram for induction welding of orthogonal lay-up thermoplastic composite materials according to the present invention.

[0061] Figure 5 The heating rate is for induction welding of the [0 / 90 / 0 / 90]CF / PEEK and CF / PPS composite materials of the present invention.

[0062] Figure 6 In this paper, a and b represent the proportions of heat generated by different heat generation mechanisms in the induction welding of [0 / 90 / 0 / 90]CF / PEEK and CF / PPS composite materials of the present invention, respectively. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in specific embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0064] Reference Figure 1-6 This invention proposes a quantitative calculation method for the multi-mechanism heat generation efficiency of induction welding of orthogonal lay-up thermoplastic composites, specifically including the following steps:

[0065] S1: Based on the microstructure of orthogonal lay-up thermoplastic composites, a heat generation model is established;

[0066] S2: Based on the established heat generation model, analyze the quantitative relationship between dielectric loss, contact resistance heating and fiber heating in the heat generation mechanism;

[0067] S3: Design induction welding tests and DSC tests for two different materials in orthogonal lay-up thermoplastic composites, and determine the heat generation;

[0068] S4: Based on the heat generation model and the analysis and test results of steps S2-S3, calculate the proportion and heat generation of different heat generation mechanisms in induction welding.

[0069] Preferably, in step S1 above, the microstructure of the thermoplastic composite material is as follows:

[0070]

[0071] Among them, Vf The volume fraction of the composite fiber is represented by 'a', the thickness of the prepreg is represented by 'd'. f Indicates the diameter of a single fiber bundle in the prepreg;

[0072] l f =a (2)

[0073] Among them, l f Indicates the fiber length in a microcircuit;

[0074]

[0075] Among them, A f Indicates the cross-sectional area of ​​the fiber;

[0076]

[0077] Among them, A j This indicates the cross-sectional area of ​​the resin matrix.

[0078] Preferably, in step S1 above, establishing the heat generation model specifically includes the following steps:

[0079] S101: Fiber heating inside carbon fiber

[0080] p f =I f 2 R f (5)

[0081] Where, p f Indicates the fiber heating power, I f R represents the fiber current in the circuit. f Indicates the electrical resistance of carbon fiber;

[0082] S102: Dielectric loss of the resin at the junction

[0083]

[0084] Where, p jd I represents dielectric loss power. jd R represents the dielectric loss current at the node. jd denoted by ε0, h represents the resin thickness, ω represents the power supply angular frequency, ε0 ​​represents the vacuum dielectric constant, k represents the dielectric constant of the resin matrix, and tanδ represents the delay angle of the resin matrix.

[0085] S103: Contact resistance heating at the junction

[0086] p jc =I jc 2 R jc (7)

[0087] Where, p jc I represents the contact resistance heating power. jc R represents the contact resistance current at the node. jc This indicates the contact resistance.

[0088] In induction welding of orthogonal lay-up thermoplastic composites, the quantitative relationship between the current in the fiber and the current at the junction is as follows:

[0089]

[0090] I f =I jc or I f =I jdt (9)

[0091] I jdt =I c +I jd (10)

[0092]

[0093] Among them, I c I represents the charging current at the dielectric loss junction. jdt This represents the total current at the dielectric loss junction.

[0094] Preferably, in step S2 above, during induction welding of orthogonal lay-up thermoplastic composite materials, the quantitative relationship between dielectric loss and fiber heating is as follows:

[0095]

[0096] Where M represents the ratio of dielectric loss in the microcircuit to fiber heating.

[0097] Preferably, in step S3 above, the quantitative relationship between contact resistance heating and fiber heating in the induction heating of orthogonal lay-up thermoplastic composite materials is as follows:

[0098]

[0099] Where N represents the ratio of contact resistance heating to fiber heating in the microcircuit.

[0100] Based on the above scheme, a further preferred embodiment of the present invention is as follows: In step S2 above, the total resistance in the thickness direction of the composite material is as follows:

[0101]

[0102] Among them, R jt This represents the total resistance along the thickness direction of the composite material.

[0103] Preferably, in step S4 above, the heat generation of the two different materials within the same time period is as follows:

[0104]

[0105] Where Q1 and Q2 represent the heat generation of composite material 1 and composite material 2, respectively; C1 and C2 represent the specific heat capacity of composite material 1 and composite material 2, respectively; m1 and m2 represent the mass of composite material 1 and composite material 2, respectively; and T represents the heat generation of composite material 1 and composite material 2, respectively. 0-1 T 0-2 and T 1-1 T 1-2 These represent the initial and final temperature values ​​of composite material 1 and composite material 2 during the induction welding test, respectively.

[0106] Preferably, in step S5 above, the proportion and heat generation relationship of the different heat generation mechanisms of the two different materials induction welding are as follows:

[0107]

[0108] Where M1 and M2 represent the ratio of dielectric loss to fiber heating in composite material 1 and composite material 2, respectively; N1 and N2 represent the ratio of contact resistance heating to fiber heating in composite material 1 and composite material 2, respectively; m and n represent the ratio of dielectric loss to contact resistance heating, respectively; and P... f1 and P f2 R represents the amount of heat generated by heating the fibers of composite material 1 and composite material 2, respectively. jt1 R jt2 These represent the total resistance in the thickness direction of composite material 1 and composite material 2, respectively.

[0109] Example:

[0110] This example uses the calculation of the heat generation mechanism of induction welding of orthogonal layered carbon fiber reinforced polyether ether ketone (CF / PEEK) and carbon fiber reinforced polyphenylene sulfide (CF / PPS) as an example, and gives the following specific implementation process.

[0111] like Figure 1 As shown, the purpose of this embodiment is to calculate the efficiency of different heat generation mechanisms in induction welding of orthogonal layered carbon fiber reinforced polyether ether ketone (CF / PEEK) and carbon fiber reinforced polyphenylene sulfide (CF / PPS). The specific implementation steps are as follows:

[0112] S1: Microstructure based on thermoplastic composite unidirectional prepreg (e.g.) Figure 2 As shown), establish heat generation models for orthogonal layup CF / PEEK and CF / PPS (e.g. Figure 3(as shown); where the prepreg thickness of CF / PEEK and CF / PPS is 15 mm and the volume fraction is 57% (i.e., the relevant dimensions in the microcircuit).

[0113] In this embodiment, the microstructure of the thermoplastic composite material is as follows:

[0114]

[0115] Among them, V f The volume fraction of the composite fiber is represented by 'a', the thickness of the prepreg is represented by 'd'. f Indicates the diameter of a single fiber bundle in the prepreg;

[0116] l f =a (2)

[0117] Among them, l f Indicates the fiber length in a microcircuit;

[0118]

[0119] Among them, A f Indicates the cross-sectional area of ​​the fiber;

[0120]

[0121] Among them, A j This indicates the cross-sectional area of ​​the resin matrix.

[0122] In this embodiment, establishing the heat generation models for orthogonal layup CF / PEEK and CF / PPS specifically includes the following steps:

[0123] S101: Fiber heating inside carbon fiber

[0124] p f =I f 2 R f (5)

[0125] Where, p f R represents the fiber heating power, I represents the fiber current in the circuit, and R represents the fiber heating power. f Indicates the electrical resistance of carbon fiber;

[0126] S102: Dielectric loss of the resin at the junction

[0127]

[0128] Where, p jd I represents dielectric loss power. jd R represents the dielectric loss current at the node. jddenoted by ε0, h represents the resin thickness, ω represents the power supply angular frequency, ε0 ​​represents the vacuum dielectric constant, k represents the dielectric constant of the resin matrix, and tanδ represents the delay angle of the resin matrix.

[0129] S103: Contact resistance heating at the junction

[0130] p jc =I jc 2 R jc (7)

[0131] Where, p jc I represents the contact resistance heating power. jc R represents the contact resistance current at the node. jc This indicates the contact resistance.

[0132] S2: Based on the dielectric properties of thermoplastic composites of orthogonal CF / PEEK and CF / PPS, a quantitative relationship between dielectric loss and fiber heating is established in the induction welding heat generation mechanism.

[0133] In this embodiment, for CF / PEEK and CF / PPS materials, the dielectric constants of PEEK and PPS are 3.3 and 3.27, respectively, and the dielectric loss tangents are 0.003 and 0.0025, respectively. The power supply frequency in induction welding is 27kHz. The quantitative relationship between dielectric loss and fiber heating during induction heating of the two orthogonal layup thermoplastic composite materials is as follows:

[0134]

[0135] Among them, M PEEK M PPS These represent the ratio of dielectric loss to fiber heating in the CF / PEEK and CF / PPS microcircuits, respectively.

[0136] S3: Based on the electrical conductivity of thermoplastic composites of orthogonal CF / PEEK and CF / PPS, a quantitative relationship between contact resistance heating and fiber heating in the heat generation mechanism of induction welding is established.

[0137] The contact resistances of CF / PEEK and CF / PPS materials were measured to be R. z_PEEK and R z_PPS The quantitative relationship between contact resistance heating and fiber heating in induction welding of orthogonal CF / PEEK and CF / PPS thermoplastic composites is as follows:

[0138]

[0139] Where, N PEEK and N PPSP represents the ratio of contact resistance heating and fiber heating in the CF / PEEK and CF / PPS microcircuits, respectively. jc_PEEK and P jc_PPS P represents the heat generated by dielectric loss in CF / PEEK and CF / PPS, respectively. f_PEEK and P f_PPS R represents the fiber heating power of CF / PEEK and CF / PPS, respectively. z_PEEK and R z_PPS These represent the contact resistances of CF / PEEK and CF / PPS, respectively.

[0140] S4: Induction welding tests and DSC tests were conducted on two different materials, CF / PEEK and CF / PPS, such as... Figure 3 As shown, the heat Q of the two materials within the same time period was obtained respectively. PEEK and Q PPS :

[0141]

[0142] Among them, Q PEEK and Q PPS The heat production of CF / PEEK and CF / PPS, respectively, is represented by C. PEEK and C PPS Let m represent the specific heat capacity of CF / PEEK and CF / PPS, respectively. PEEK and m PPS T represents the mass of CF / PEEK and CF / PPS respectively. 0_PEEK T 0_PPS and T 1_PEEK T 1_PPS These represent the initial and final temperature values ​​for CF / PEEK and CF / PPS, respectively.

[0143] S5: Based on the heat generation model and the measured heat generation, the proportion and heat generation of different heat generation mechanisms in induction welding are calculated. The heat generation relationship between orthogonal layup CF / PEEK and CF / PPS induction welding is as follows:

[0144]

[0145] Where m and n represent the ratio of dielectric loss and contact resistance heating, respectively.

[0146] After the above experimental process, the following results were obtained: Figure 5The graph shows the heating rate of [0 / 90 / 0 / 90] CF / PEEK and CF / PPS composite materials under induction heating over time. It can be seen that the heating rate of CF / PEEK composite material is significantly lower than that of CF / PPS composite material. This phenomenon is due to the fact that the specific heat capacity of CF / PEEK composite material is significantly higher than that of CF / PPS composite material. When the heat generation is the same, the temperature rise of CF / PEEK composite material is lower.

[0147] Using the method of this invention, the proportions of dielectric loss and contact resistance heating at the joints of [0 / 90 / 0 / 90]CF / PEEK and CF / PPS composite laminates were calculated to be m = 0.0011 and n = 0.9989, respectively. Meanwhile, in the induction welding of composite laminates, the resistance heating in the fibers is 6 to 7 orders of magnitude smaller than the dielectric loss and contact resistance heating at the joints, and therefore can be almost ignored.

[0148] In induction welding of [0 / 90 / 0 / 90]CF / PEEK and CF / PPS composite materials, calculations show that the ratio of dielectric loss to heat generation from contact resistance heating for the two materials is mgM. PEEK ngN PEEK =2.0192, mgM PPS ngN PPS =4.7294, indicating that dielectric loss is the dominant heat generation mechanism at the junction. The heat generation proportions of dielectric loss in the two composite materials are 0.6688 and 0.8255, respectively. Under induction welding conditions, the proportions of heat generation from fiber heating, dielectric loss, and contact resistance heating in [0 / 90 / 0 / 90]CF / PEEK and CF / PPS materials are as follows: Figure 6 As shown.

[0149] Therefore, under the molding process and induction welding conditions described in the method of this invention, dielectric loss is the dominant heat generation mechanism in induction welding of orthogonal lay-up carbon fiber reinforced thermoplastic composites.

[0150] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. For those skilled in the art, the technical solutions and concepts of the present invention can have various equivalent substitutions and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A quantitative calculation method for the multi-mechanism heat generation efficiency of induction welding of orthogonal lay-up thermoplastic composites, characterized in that, Includes the following steps: S1: Based on the microstructure of orthogonal lay-up thermoplastic composites, a heat generation model is established; S2: Based on the established heat generation model, the quantitative relationship between dielectric loss, contact resistance heating, and fiber heating in the heat generation mechanism is analyzed. In induction welding of orthogonal lay-up thermoplastic composites, the quantitative relationship between the current in the fiber and the current at the junction is as follows: （8） （9） （10） （11） Among them, I c I represents the charging current at the dielectric loss junction. jdt This represents the total current at the dielectric loss junction. This represents the fiber current in the circuit. This represents the dielectric loss current at the node. This represents the contact resistance current at the node; S3: Design induction welding tests and DSC tests for two different materials in orthogonal lay-up thermoplastic composites, and determine the heat generation; S4: Based on the heat generation model and the analysis and test results of steps S2 and S3, calculate the proportion and heat generation of different heat generation mechanisms in induction welding. The relationship between the proportion and heat generation of different heat generation mechanisms in induction welding of two different materials is as follows: （16） Where M1 and M2 represent the ratio of dielectric loss to fiber heating in composite material 1 and composite material 2, respectively; N1 and N2 represent the ratio of contact resistance heating to fiber heating in composite material 1 and composite material 2, respectively; and m and n represent the proportions of dielectric loss and contact resistance heating, respectively. and These represent the heat generation of composite material 1 and composite material 2, respectively. and R represents the amount of heat generated by heating the fibers of composite material 1 and composite material 2, respectively. jt1 R jt2 These represent the total resistance in the thickness direction of composite material 1 and composite material 2, respectively.

2. The quantitative calculation method for multi-mechanism heat generation efficiency in induction welding of orthogonal lay-up thermoplastic composites according to claim 1, characterized in that, In step S1 above, the microstructure of the thermoplastic composite material is as follows: （1） where V f represents the volume fraction of the composite fibers, a represents the thickness of the prepreg, d f represents the diameter of the individual fiber bundle in the prepreg; （2） in, Indicates the fiber length in a microcircuit; （3） wherein A f represents the cross-sectional area of the fiber; （4） in, This indicates the cross-sectional area of ​​the resin matrix.

3. The quantitative calculation method for multi-mechanism heat generation efficiency in induction welding of orthogonal lay-up thermoplastic composites according to claim 2, characterized in that, In step S1 above, establishing the heat generation model specifically includes the following steps: S101: Fiber heating inside carbon fiber （5） in, Indicates the fiber heating power. This represents the fiber current in the circuit. Indicates the electrical resistance of carbon fiber; S102: Dielectric loss of the resin at the junction （6） in, Indicates dielectric loss power. R represents the dielectric loss current at the node. jd The dielectric loss resistance of the resin is represented by h, the resin thickness is represented by ω, and the power supply angular frequency is represented by ω. Let k represent the vacuum dielectric constant, and k represent the dielectric constant of the resin matrix. Indicates the retardation angle of the resin matrix; S103: Contact resistance heating at the junction （7） in, Indicates the contact resistance heating power. This represents the contact resistance current at the node. This indicates the contact resistance.

4. The quantitative calculation method for multi-mechanism heat generation efficiency in induction welding of orthogonal lay-up thermoplastic composites according to claim 3, characterized in that, In step S2 above, during induction welding of orthogonal lay-up thermoplastic composite materials, the quantitative relationship between dielectric loss and fiber heating is as follows: （12） Where M represents the ratio of dielectric loss in the microcircuit to fiber heating.

5. The quantitative calculation method for multi-mechanism heat generation efficiency in induction welding of orthogonal lay-up thermoplastic composites according to claim 4, characterized in that, In step S2 above, during induction welding of orthogonal lay-up thermoplastic composite materials, the quantitative relationship between contact resistance heating and fiber heating is as follows: （13） Where N represents the ratio of contact resistance heating to fiber heating in the microcircuit.

6. The quantitative calculation method for multi-mechanism heat generation efficiency in induction welding of orthogonal lay-up thermoplastic composites according to claim 5, characterized in that, In step S2 above, the total resistance in the thickness direction of the composite material is as follows: （14） in, This represents the total resistance along the thickness direction of the composite material.

7. The quantitative calculation method for multi-mechanism heat generation efficiency in induction welding of orthogonal lay-up thermoplastic composites according to claim 6, characterized in that, In step S3 above, the heat generated by the two different materials within the same time period is as follows: （15） in, and These represent the heat generation of composite material 1 and composite material 2, respectively. and These represent the specific heat capacities of composite material 1 and composite material 2, respectively. and These represent the masses of composite material 1 and composite material 2, respectively. , and , These represent the initial and final temperature values ​​of composite material 1 and composite material 2 during the induction welding test, respectively.

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