A programming calculation method for the moment of inertia of the engine connecting rod section

Abstract

The present invention relates to the field of engineering design of engine connecting rods, and specifically to a programming calculation method for the inertia moment of an engine connecting rod section; comprising: obtaining the shape and size parameters of the connecting rod section by measuring; deriving the equations of each line segment of the connecting rod section by geometry; accurately calculating the coordinates of the transition points of each line segment of the connecting rod section by equations; programming calculation of the inertia moment of the connecting rod section by applying the definite integral approximation principle; the shape and size parameters of the connecting rod section include the transition arc radius, the height of the connecting rod section, the vertex angle, etc.; the present invention overcomes the problem that the calculation of the inertia moment of the engine connecting rod section in the prior art needs to rely on the connecting rod CAD model, and when the shape of the connecting rod section changes, the connecting rod CAD model needs to be regenerated, and the section inertia moment cannot be automatically calculated according to the connecting rod section parameters, and provides a programming calculation method for the inertia moment of the engine connecting rod section. The present invention has the advantages of parameterization and high calculation efficiency.

Description

Technical Field

[0001] The present invention relates to the field of engineering design of engine connecting rods, and in particular to a numerical method for calculating the moment of inertia of an arbitrary cross-section of an engine connecting rod, and more specifically to a programming calculation method for calculating the moment of inertia of a cross-section of an engine connecting rod. Background Art

[0002] Patent document 1 (CN201510346424.8) discloses a method for calculating the buckling load of a rod to be tested with elastic constraints at both ends. The method for calculating the buckling load of a rod to be tested with elastic constraints at both ends, wherein the buckling stress of the rod to be tested (1) does not exceed the proportional limit of the material of the rod to be tested, is characterized in that the method comprises the following steps: Step 1: obtaining the material parameters of the rod to be tested (1); Step 2: calculating the column end rotation constraint stiffness parameter α of the rod to be tested (1) by a formula based on the material parameters of the rod to be tested (1); Step 3: calculating the buckling load of the rod to be tested (1) according to the formula based on the data in Step 1 and Step 2.

[0003] Patent document 2 (CN201510250001.6) provides a method for calculating the elastic-plastic buckling load of an axially compressed member, comprising the following steps: (1) dividing the cross section of the axially compressed member into a plurality of units to form a cross-sectional grid; (2) determining the yield type of the axially compressed member; (3) calculating the value of the corresponding chord-intercept interval point, the buckling function value at the initial value of the buckling load, and the buckling function value at the chord-intercept interval point according to the determined yield type; (4) calculating the value of the secant point; (5) determining whether the iteration is completed according to the convergence condition; if so, outputting the elastic-plastic buckling load; otherwise, resetting the initial value of the buckling load and the value of the chord-intercept interval point and returning to step (3).

[0004] Patent document 3 (CN201510825123.3) discloses a post-buckling load design method for axially compressed stiffened panels, which belongs to the field of aircraft structure design. The method includes first calculating the initial buckling load of the axially compressed stiffened panels and the failure load of the axially compressed stiffened panels according to the cross-sectional parameters of the axially compressed stiffened panels, the rib spacing b, the rib spacing a, and the skin thickness t. Finally, the ratio n of the failure load of the axially compressed stiffened panels to the initial buckling load of the axially compressed stiffened panels is calculated, and the values ​​of a, b, and t are reset until n meets the preset values, thereby achieving an efficient design of the post-buckling load of the axially compressed stiffened panels. Through this method, the metal axially compressed panels with the highest structural weight efficiency under the load requirements can be designed; the design method is combined with a semi-theoretical and semi-empirical formula for accurately predicting the failure stress, and is simple and convenient to use.

[0005] However, the above patent documents do not involve the content of the present invention. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the problem that the calculation of the engine connecting rod section inertia moment needs to rely on the connecting rod CAD model in the prior art, and when the connecting rod cross-sectional shape changes, the connecting rod CAD model needs to be regenerated, and the section inertia moment cannot be automatically calculated according to the connecting rod section parameters. A programming calculation method for the engine connecting rod section inertia moment is provided.

[0007] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0008] In order to solve the above technical problems, the present invention is implemented by adopting the following technical solutions:

[0009] A programming calculation method for the moment of inertia of an engine connecting rod section comprises:

[0010] Obtain the connecting rod cross-sectional shape and size parameters by measuring;

[0011] Derive the equations of each line segment of the connecting rod cross section by geometry;

[0012] The coordinates of the transition points of each line segment of the connecting rod section are accurately calculated through equations;

[0013] The definite integral approximation principle is used to program the calculation of the moment of inertia of the connecting rod section.

[0014] The connecting rod cross-sectional shape and size parameters described in the technical solution include transition arc radius, connecting rod cross-sectional height, and vertex angle.

[0015] Furthermore, the specific method of deriving the equations of each line segment of the connecting rod cross section by geometry is as follows:

[0016] Based on the geometric relationship of the connecting rod cross section, the mathematical equations of each line segment of the connecting rod cross section are derived;

[0017] Taking the first quadrant as an example, the cross-sectional shape is divided into six segments, and the mathematical equation is as follows:

[0018] The mathematical expression for the line segment number being 1 and the line segment type being a straight line is:

[0019] The mathematical expression for the line segment number 2 and the line segment type arc is: (x-x3) 2+(y-y3) 2 =r1 2 ;

[0020] The line segment number is 3, and the line segment type is a straight line. The mathematical expression is: x = x4;

[0021] The line segment number is 4, and the line segment type is arc. The mathematical expression is: (x-x7) 2 +(y-y7) 2 =r1 2 ;

[0022] The mathematical expression for the line segment number 5 and the line segment type arc is:

[0023] The line segment number is 6, and the mathematical expression of the line segment type is straight line: x=x9.

[0024] The letters x and y represent the coordinate axes, and the subscripts 1 to 9 of x represent the numbers 1 to 9 respectively; r represents the radius of the arc, and the subscripts 1 to 2 of r represent the number of the arc;

[0025] Furthermore, the coordinates of the transition points of each line segment of the connecting rod section are accurately calculated by the equation, and the specific method is as follows:

[0026] According to the mathematical equations of each line segment and the shape and size parameters of the connecting rod section, the coordinates of the transition points of each line segment of the connecting rod section are accurately calculated. The calculation formula is as follows:

[0027] x1=0

[0028] y1=a

[0029] x2=b-r1+r1 cosφ

[0030] y2=a-(b-r1+r1 cosφ) / tanφ

[0031] x3=b-r1

[0032] y3=ab / tanφ-rtan(φ / 2)

[0033] x4=b

[0034] y4=ab / tanφ-r·tan(φ / 2)

[0035] x5=b

[0036] y5=ab / tanφ-r / tan(φ / 2)-(d-2tan(φ / 2))

[0037] Where: a represents 1 / 2 of the height of the I-beam;

[0038] b represents 1 / 2 of the length of the I-beam crossbeam;

[0039] r1 represents the chamfer radius of the I-beam crossbeam;

[0040] r2 represents the chamfer radius of the vertical beam of the I-beam;

[0041] φ represents 1 / 2 of the top angle of the connecting rod section.

[0042] Furthermore, the application of the definite integral approximation principle to program the calculation of the moment of inertia of the connecting rod section is as follows:

[0043] According to the formula for calculating the moment of inertia and the formula for parallel axis displacement, the connecting rod section is divided into several rectangular sections, and the moments of inertia of several rectangular areas are calculated respectively. The moment of inertia of a single area is calculated by applying the integral approximation principle.

[0044] The cross-sectional shape of the connecting rod is replaced by the approximation of several rectangular parts;

[0045] The moment of inertia of a combined figure about a certain axis is equal to the sum of the moments of inertia of each part of the figure about the same axis;

[0046]

[0047] Where: I y represents the total moment of inertia of the cross section about the Y axis;

[0048] I yi Represents the moment of inertia of the i-th rectangle divided about the Y axis;

[0049] n represents the total number of equal parts into which the connecting rod cross section is divided;

[0050] i represents the serial number of one of the parts into which the connecting rod cross section is divided;

[0051] The programming method is used to calculate the moment of inertia of the connecting rod section. The Excel-VBA language is used to program and numerically solve the moment of inertia of the connecting rod section.

[0052] Further, Excel-VBA language programming:

[0053]

[0054] Furthermore, the accuracy of the calculation results of Excel-VBA language programming is related to the number of parts the connecting rod section is divided into. When the number of parts the connecting rod section is divided into is greater than 200, the result difference is less than 0.01%.

[0055] Furthermore, the integral approximation principle refers to using definite integrals to solve the problem in three steps: segmentation, approximate substitution, and summation; segmentation: segmenting the connecting rod cross section into a number of rectangles;

[0056] Approximate substitution: replace the moment of inertia of the continuous surface with the moment of inertia of the segmented part;

[0057] Sum: Sum the moments of inertia of the divided rectangles.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] The invention proposes a method for expressing the cross-sectional shape of an engine connecting rod by applying a mathematical formula, and proposes a computer numerical method for calculating the moment of inertia of a rod cross section, which has the advantages of parameterization and high calculation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The present invention will be further described below in conjunction with the accompanying drawings:

[0061] Figure 1 is a schematic diagram of the section moment of inertia;

[0062] Figure 2 It is a schematic diagram of the parallel translation axis of the moment of inertia of a cross section of arbitrary shape;

[0063] Figure 3 Schematic diagram of the calculation method of the moment of inertia of the rectangular axis;

[0064] Figure 4 It is a schematic diagram of the cross section of the engine connecting rod;

[0065] Figure 5 Schematic diagram of calculating the moment of inertia of the connecting rod section using hypermesh software;

[0066] Figure 6 It is a schematic diagram of the cross section of the engine connecting rod;

[0067] Figure 7 A flow chart of the steps for calculating the moment of inertia of the engine connecting rod section;

[0068] Figure 8 This is a schematic diagram of the measurement dimension parameters of the engine connecting rod cross section;

[0069] Fig. 9 It is a schematic diagram of the cross-section line segments and transition points of the engine connecting rod;

[0070] Fig.10 It is a schematic diagram of the approximate substitution of the connecting rod cross-section shape;

[0071] Fig.11a The curve showing the relationship between the calculation result of the moment of inertia of the connecting rod section and the number of divisions Figure 1 ;

[0072] Fig.11b The curve showing the relationship between the calculation result of the moment of inertia of the connecting rod section and the number of divisions Figure 2 ;

[0073] Fig.12a This is an example of application of the present invention Figure 1 ;

[0074] Figure 12b This is an example of application of the present invention Figure 2 . DETAILED DESCRIPTION

[0075] In order to make the purpose, technical scheme and advantages of the implementation of the present invention clearer, the technical scheme in the embodiment of the present invention will be described in more detail below in conjunction with the drawings in the embodiment of the present invention. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of the present invention, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limitations on the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The embodiments of the present invention are described in detail below in conjunction with the drawings.

[0076] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present invention.

[0077] The present invention is described in detail below in conjunction with the accompanying drawings:

[0078] First, we introduce the theoretical calculation method of the moment of inertia. For any cross-section, such as Figure 1 , Figure 2 , whose area is A, x, y are any pair of rectangular coordinate axes in the cross-sectional plane. Take any micro area dA from the cross section, whose coordinate axes are y and z, then y 2 dA and z 2 dA is called the moment of inertia of the micro area dA about the z axis and the y axis respectively (if dA is regarded as mass, then y 2 dA and z 2 dA is equivalent to the moment of inertia in dynamics, and is called moment of inertia because of the similarity in form); the integral of the entire cross-sectional area A:

[0079] I z =∫ A y 2 dA

[0080] I y =∫ A z 2 dA……(1)

[0081] Where: I z ——the moment of inertia of the section about the z-axis;

[0082] I y ——The moment of inertia of the section about the y-axis.

[0083] For any cross section, Figure 2 , C is the centroid, a and b are the coordinates of the centroid of the cross section in the y and z coordinate systems, and the moment of inertia can be calculated using the parallel axis formula:

[0084] I y =I yc +a 2 ·A

[0085] I z =I zc +b 2 ·A……(2)

[0086] Where: I yc ——the moment of inertia of the section with the y-axis as the centroidal axis;

[0087] I zc ——The moment of inertia of the cross section with the z-axis as the centroidal axis.

[0088] Calculate the moment of inertia I of a rectangular cross section about its symmetry axes y and z y and I z .

[0089] like Figure 3 , take the narrow strip parallel to the z-axis as the micro area dA, then dA = b·dy, according to the definition of moment of inertia:

[0090]

[0091] Using exactly the same method to solve dA = h·dz, we can obtain:

[0092] When calculating the deformation of a rod under external force, some geometric quantities of the cross section of the rod are involved. The bending force and deformation of the engine connecting rod are related to the moment of inertia of the cross section. It is of great engineering significance to explore the calculation method of the moment of inertia of the engine connecting rod cross section.

[0093] The shape of the engine connecting rod cross section is generally similar to the "I-beam" structure. In the engineering design of the engine connecting rod cross section, the cross section is usually sketched using CAD software first, and then the detailed design of details such as chamfers is carried out. Figure 4 .

[0094] At present, the calculation of engine connecting rod section inertia moment is mainly realized by using tool software. Taking Hypermesh software as an example, the calculation steps include: ① Importing the engine connecting rod CAD model; ② Obtaining the connecting rod cross-section graphics; ③ Section mesh division; ④ Calculating the section inertia moment. Figure 5 .

[0095] The present invention proposes a programming calculation method for the inertia moment of the connecting rod section of an engine commonly used in engineering, and its applicable scope is as follows: ① the radius of arc 1 and arc 2 are the same; ② the transition point of arc 2 and arc 3 is tangent; Figure 6 .

[0096] The present invention proposes a theoretical calculation method for the moment of inertia of the engine connecting rod section, and the steps for implementing the method are as follows:

[0097] Obtain the connecting rod cross-sectional shape and size parameters by measuring;

[0098] Derive the equations of each line segment of the connecting rod cross section by geometry;

[0099] The coordinates of the transition points of each line segment in the connecting rod section are precisely determined by equations;

[0100] Programmable numerical calculation of the moment of inertia of the connecting rod section about the Y or Z axis.

[0101] The technical content of the above steps is elaborated below:

[0102] Step 1: Obtain connecting rod interface design parameters

[0103] The connecting rod cross-section shape and size parameters are obtained by measurement, such as transition arc radius, connecting rod cross-section height, etc.

[0104] The detailed design size parameters that need to be measured are as follows:

[0105] a is 1 / 2 of the height of the I-beam, b is 1 / 2 of the length of the horizontal beam of the I-beam, c is 1 / 2 of the width of the vertical beam of the I-beam, d is the distance between the two centers of the chamfer of the horizontal beam, r1 is the chamfer radius of the horizontal beam of the I-beam, r2 is the chamfer radius of the vertical beam of the I-beam, φ is 1 / 2 of the top angle of the connecting rod.

[0106] Step 2: Analysis of the cross-sectional shape formula

[0107] Based on the geometric relationship of the connecting rod cross section, the mathematical equations of each line segment of the connecting rod cross section are derived.

[0108] Taking the first quadrant (x>0, y>0) as an example, the cross-sectional shape is divided into six segments, and the mathematical equations are as follows:

[0109] The mathematical expression for the line segment number being 1 and the line segment type being a straight line is:

[0110] The mathematical expression for the line segment number 2 and the line segment type arc is: (x-x3) 2 +(y-y3) 2 =r1 2

[0111] The line segment number is 3, and the line segment type is a straight line. The mathematical expression is: x = x4

[0112] The line segment number is 4, and the line segment type is arc. The mathematical expression is: (x-x7) 2 +(y-y7) 2 =r1 2

[0113] The mathematical expression for the line segment number 5 and the line segment type arc is:

[0114] The line segment number is 6, and the line segment type is a straight line. The mathematical expression is: x = x9

[0115] The line segments and node coordinates of the connecting rod section in the first quadrant are shown in Fig. 9 .

[0116] Step 3: Transition point coordinate calculation

[0117] According to the mathematical equations of each line segment in step 2 and the design parameters of step 1, taking the first quadrant (x>0, y>0) as an example, the coordinates of the transition points of each line segment of the connecting rod section are accurately calculated. The calculation formulas for some nodes are as follows:

[0118] x1=0

[0119] y1=a

[0120] x2=b-r1+r1cosφ

[0121] y2=a-(b-r1+r1cosφ) / tanφ

[0122] x3=b-r1

[0123] y3=ab / tanφ-rtan(φ / 2)

[0124] x4=b

[0125] y4=ab / tanφ-r·tan(φ / 2)

[0126] x5=b

[0127] y5=ab / tanφ-r / tan(φ / 2)-(d-2tan(φ / 2))

[0128] Where: a represents 1 / 2 of the height of the I-beam;

[0129] b represents 1 / 2 of the length of the I-beam crossbeam;

[0130] r1 represents the chamfer radius of the I-beam crossbeam;

[0131] r2 represents the chamfer radius of the vertical beam of the I-beam;

[0132] φ represents 1 / 2 of the top angle of the connecting rod section.

[0133] x1, x2, x3, x4, x5——x-axis coordinate values ​​of points numbered 1, 2, 3, 4, 5;

[0134] y1, y2, y3, y4, y5 - the y-axis coordinate values ​​of the points numbered 1, 2, 3, 4, 5.

[0135] Step 4: Approximate calculation of the integral of the moment of inertia of the connecting rod section about the Y axis

[0136] According to the calculation formula of the moment of inertia and the parallel axis formula, the connecting rod section is divided into several rectangular sections, and the moments of inertia of several rectangular areas are calculated respectively. The moment of inertia of a single area is calculated using the integral approximation principle.

[0137] The cross-sectional shape of the connecting rod can be replaced by a number of rectangular approximations, such as Fig.10 .

[0138] The moment of inertia of a combined figure has the following characteristics: the moment of inertia of a combined figure about a certain axis is equal to the sum of the moments of inertia of each part of the figure about the same axis.

[0139]

[0140] Where: I y ——Total moment of inertia of the cross section about the Y axis;

[0141] I yi ——The moment of inertia of the i-th divided rectangle about the Y axis.

[0142] The numerical programming solution of definite integral can usually be divided into three steps: division, approximate substitution, and summation.

[0143] The present invention adopts a programming method to calculate the moment of inertia of the connecting rod section, which has three steps: (1) segmentation: segment the connecting rod section into a number of rectangles; (2) approximate substitution: replace the moment of inertia of the continuous surface with the moment of inertia of the segmented part; (3) summation: sum the moments of inertia of the segmented rectangles. The program will automatically calculate the value of the moment of inertia of the connecting rod section, and as long as the number of segments is large enough, the calculation result will have sufficient accuracy.

[0144] Using Excel-VBA programming language, the moment of inertia of the connecting rod section is numerically solved. VBA program example:

[0145]

[0146] The accuracy of the calculation result is related to the number of parts into which the connecting rod section is divided. The calculation results of the moment of inertia calculated using the program of the present invention show that when the number of parts into which the connecting rod section is divided is greater than 200, the difference in the results is less than 0.01%.

[0147] The present invention can be applied to the calculation of the connecting rod buckling load and the connecting rod cross-sectional area. Fig.12a , Figure 12b shown.

[0148] The invention protects a mathematical analysis method for the cross-sectional shape of a connecting rod of an engine, a numerical calculation method for the moment of inertia of the connecting rod cross-sectional shape, and a computer programming method for realizing the above process by using VBA language.

[0149] Some CAD and CAE software provide the function of calculating the moment of inertia, such as hypermesh, etc. However, the above software requires a three-dimensional or two-dimensional data model of the connecting rod. When the connecting rod cross-sectional dimension parameters change, the three-dimensional or two-dimensional data model needs to be regenerated, and automatic calculation cannot be performed based on the parameterized connecting rod cross-sectional dimensions.

[0150] The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any modification, equivalent replacement and improvement made by any person skilled in the art within the technical scope disclosed by the present invention and within the spirit and principle of the present invention shall be covered within the protection scope of the present invention. At the same time, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

Claims

1. A programming calculation method for the moment of inertia of the engine connecting rod section, characterized in that: include: Obtain the connecting rod cross-sectional shape and size parameters by measuring; Derive the equations of each line segment of the connecting rod cross section by geometry; The coordinates of the transition points of each line segment of the connecting rod section are accurately calculated through equations; Apply the definite integral approximation principle to program the calculation of the moment of inertia of the connecting rod section; The connecting rod cross-section shape and size parameters include transition arc radius, connecting rod cross-section height, and vertex angle; The specific method of deriving the equations of each line segment of the connecting rod cross section by geometry is as follows: Based on the geometric relationship of the connecting rod cross section, the mathematical equations of each line segment of the connecting rod cross section are derived; The cross-sectional shape in the first quadrant is divided into six segments, and the mathematical equation is as follows: The mathematical expression for the line segment number being 1 and the line segment type being a straight line is: The mathematical expression for the line segment number 2 and the line segment type arc is: (x-x3) 2 +(y-y3) 2 =r1 2 ; The line segment number is 3, and the line segment type is a straight line. The mathematical expression is: x = x4; The line segment number is 4, and the line segment type is arc. The mathematical expression is: (x-x7) 2 +(y-y7) 2 =r1 2 ; The mathematical expression for the line segment number 5 and the line segment type arc is: The line segment number is 6, and the mathematical expression of the line segment type is straight line: x=x9; The letters x and y represent the coordinate axes, and the subscripts 1 to 9 of x represent the numbers 1 to 9 respectively; r represents the radius of the arc, and the subscripts 1 to 2 of r represent the number of the arc; The coordinates of the transition points of each line segment of the connecting rod section are accurately calculated by the equation, and the specific method is as follows: According to the mathematical equations of each line segment and the shape and size parameters of the connecting rod section, the coordinates of the transition points of each line segment of the connecting rod section are accurately calculated. The calculation formula is as follows: x1＝0 y1=a x2=b-r1+r1cosφ y2=a-(b-r1+r1cosφ) / tanφ x4=b y4=ab / tanφ-r1tan(φ / 2) x5=b y5=ab / tanφ-r1tan(φ / 2)-(d-2tan(φ / 2)) Where: a represents 1 / 2 of the height of the I-beam; b represents 1 / 2 of the length of the I-beam crossbeam; r1 represents the chamfer radius of the I-beam crossbeam; r2 represents the chamfer radius of the vertical beam of the I-beam; φ represents 1 / 2 of the top angle of the connecting rod section.

2. The programming calculation method of the engine connecting rod section inertia moment according to claim 1 is characterized by: The application of the definite integral approximation principle to program the calculation of the moment of inertia of the connecting rod section is as follows: According to the formula for calculating the moment of inertia and the formula for parallel axis displacement, the connecting rod section is divided into several rectangular sections, and the moments of inertia of several rectangular areas are calculated respectively. The moment of inertia of a single area is calculated by applying the integral approximation principle. The cross-sectional shape of the connecting rod is replaced by the approximation of several rectangular parts; The moment of inertia of a combined figure about a certain axis is equal to the sum of the moments of inertia of each part of the figure about the same axis; Where: I y represents the total moment of inertia of the cross section about the Y axis; I yi Represents the moment of inertia of the i-th rectangle divided about the Y axis; n represents the total number of equal parts into which the connecting rod cross section is divided; i represents the serial number of one of the parts into which the connecting rod cross section is divided; The programming method is used to calculate the moment of inertia of the connecting rod section. Excel-VBA language is used to program and numerically solve the moment of inertia of the connecting rod section.

3. The programming calculation method of the engine connecting rod section inertia moment according to claim 2 is characterized in that: The accuracy of the calculation results of Excel-VBA language programming is related to the number of parts the connecting rod section is divided into. When the number of parts the connecting rod section is divided into is greater than 200, the result difference is less than 0.01%.

4. The programming calculation method of the engine connecting rod cross-sectional inertia moment according to claim 3 is characterized in that: The integral approximation principle refers to the use of definite integrals to solve the problem in three steps: division, approximate substitution, and summation; Split: Split the connecting rod cross section into several rectangles; Approximate substitution: replace the moment of inertia of the continuous surface with the moment of inertia of the segmented part; Sum: Sum the moments of inertia of the divided rectangles.

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