A comprehensive evaluation method for static strength of aircraft structures based on data correlation

Abstract

The present application belongs to the field of aircraft structure strength design, and particularly relates to a method for comprehensive evaluation of aircraft structure static strength based on data correlation. The method includes: constructing an aircraft structure static strength index system, including: dividing the whole aircraft into multiple fuselage structures; determining the aircraft structure static strength index corresponding to each fuselage structure, with a hierarchical first-level strength index and a second-level mechanical performance index; quantitatively characterizing the allowable stress of the second-level mechanical performance index; obtaining the working stress of the second-level mechanical performance index through a virtual test of the whole aircraft; calculating the working safety margin of the second-level mechanical performance index based on the allowable stress and the working stress; obtaining the design safety margin of the second-level mechanical performance index, and scoring the first-level strength index based on the data correlation between the working safety margin and the design safety margin; scoring the fuselage structure based on the first-level strength index, and conducting a comprehensive evaluation of the static strength of the aircraft structure based on the score of the fuselage structure.

Description

Technical Field

[0001] The present application belongs to the field of aircraft structure strength design, and in particular relates to a comprehensive evaluation method for static strength of aircraft structures based on data correlation. Background Art

[0002] With the gradual improvement of aircraft structural strength technology system, structural strength has evolved from the single safety in the past to a comprehensive safety, stability, reliability, comfort and environmental adaptability. The service environment of future civil aircraft will be more complex, and all factors affecting safety in flight need to be considered during design. The requirements for structural strength have gradually evolved from qualitative evaluation to quantitative evaluation.

[0003] The current aircraft structural strength evaluation lacks the guidance of an index system and cannot accurately and quantitatively give the performance of structural strength and the systematic residual strength value, which has become an important bottleneck restricting the forward design of civil aircraft. In addition, in terms of the comprehensive evaluation method of aircraft structural strength, due to the insufficient coverage of the strength evaluation index system and the lack of corresponding scoring and evaluation strategies, qualitative evaluation of strength performance is generally carried out, and quantitative evaluation of each detailed structural strength index cannot be given, making it difficult to provide support for the comprehensive, refined and quantitative evaluation of civil aircraft structures.

[0004] Therefore, it is desired to have a technical solution to overcome or at least alleviate at least one of the above-mentioned defects of the prior art. Summary of the invention

[0005] The purpose of the present application is to provide a comprehensive static strength assessment method for aircraft structures based on data correlation to solve at least one problem existing in the prior art.

[0006] The technical solution of this application is:

[0007] A comprehensive evaluation method for static strength of aircraft structure based on data correlation, comprising:

[0008] Step 1: Construct an aircraft structure static strength index system, including:

[0009] Divide the whole machine into multiple body structures;

[0010] Determining the aircraft structure static strength index corresponding to each of the fuselage structures, wherein the aircraft structure static strength index includes a primary strength index and a secondary mechanical performance index having a hierarchical relationship;

[0011] Step 2: quantitatively characterize the allowable stress of the secondary mechanical performance index;

[0012] Step 3: obtaining the working stress of the secondary mechanical performance index through a whole machine virtual test;

[0013] Step 4: Calculate the working safety margin of the secondary mechanical performance index according to the allowable stress and the working stress;

[0014] Step 5: obtaining the design safety margin of the secondary mechanical performance index, and scoring the primary strength index according to the data correlation between the working safety margin and the design safety margin;

[0015] Step 6: Score the fuselage structure according to the first-level strength index, and conduct a comprehensive assessment of the static strength of the aircraft structure based on the score of the fuselage structure.

[0016] In at least one embodiment of the present application, in step 1, the whole machine is divided into multiple body structures, including:

[0017] Dividing the whole aircraft into multiple fuselage structures, the fuselage structure includes: wing structure, fuselage structure, aileron structure, flap structure, elevator structure, rudder structure, bracket and landing gear structure;

[0018] Determining the aircraft structure static strength index corresponding to each of the fuselage structures includes:

[0019] The first-level strength indicators corresponding to the wing structure and the fuselage structure include: panel strength, beam and rib strength, frame strength, key connection strength, and opening strength;

[0020] The first-level strength indicators corresponding to the aileron structure, the flap structure, the elevator structure and the rudder structure include: wall panel strength, beam and rib strength, frame strength, and key connection strength;

[0021] The first-level strength indicators corresponding to the bracket and landing gear structure include: key connection strength;

[0022] The secondary mechanical performance indicators corresponding to the wall panel strength include: wall panel tensile strength, wall panel compression strength, wall panel shear strength, wall panel compression shear buckling, wall panel tension shear buckling;

[0023] The secondary mechanical performance indicators corresponding to the beam and rib strength include: flange tensile strength, web stability, and web strength;

[0024] The secondary mechanical performance indicators corresponding to the frame strength include: frame edge strip tensile strength, frame edge strip compression strength, frame web tensile strength, frame web compression strength, rib tensile strength, rib compression strength;

[0025] The secondary mechanical performance indicators corresponding to the key connection strength include: connection body strength and connection area strength;

[0026] The secondary mechanical performance indicators corresponding to the opening strength include: opening plate strength and reinforcement opening strength.

[0027] In at least one embodiment of the present application, in step 2, the allowable stress of the secondary mechanical performance index is quantitatively characterized, including:

[0028] The quantitative characterization method for determining the allowable stress of each of the secondary mechanical performance indicators includes:

[0029] The allowable stress of the wall panel tensile strength, the edge strip tensile strength, the frame edge strip tensile strength, the frame web tensile strength and the rib tensile strength is quantitatively characterized by using the tensile limit stress;

[0030] The allowable stress of the wall panel compression strength, the frame edge strip compression strength, the frame web compression strength and the rib compression strength is quantitatively characterized by compression loss stress;

[0031] The allowable stress of the wall plate shear strength and the web plate strength is quantitatively characterized by the shear limit stress;

[0032] The allowable stresses of the wall plate compression shear buckling, the wall plate tension shear buckling and the web plate stability are quantitatively characterized by using the critical buckling stress;

[0033] The allowable stress of the connection body strength and the perforated plate strength is quantitatively characterized by the maximum allowable shear stress;

[0034] The allowable stress of the connection zone strength is quantitatively characterized by extrusion stress;

[0035] The allowable stress of the reinforcement mouth strength is quantitatively characterized by the average longitudinal normal stress;

[0036] According to the quantitative representation method of the allowable stress of each of the secondary mechanical performance indicators, the allowable stress of each of the secondary mechanical performance indicators is calculated by a theoretical formula;

[0037] According to the above method, the allowable stress of all secondary mechanical performance indicators of the n first-level strength indicators corresponding to the k-th fuselage structure under the j-th load condition is obtained. .

[0038] In at least one embodiment of the present application, in step three, obtaining the working stress of the secondary mechanical performance index through a whole machine virtual test includes:

[0039] Construct a finite element model for virtual testing of the entire machine;

[0040] Applying constraints on the whole machine virtual test finite element model;

[0041] Arranging load application points on the whole machine virtual test finite element model, applying loads at the load application points, gradually increasing the load from the initial load to 150% of the limit load, and obtaining the whole machine stress distribution under the jth load condition respectively;

[0042] Extract the tensile limit stress under 150% limit load from the whole machine stress distribution as the working stress of the wall panel tensile strength, the edge strip tensile strength, the frame edge strip tensile strength, the frame web tensile strength and the rib tensile strength;

[0043] Extract the compressive limit stress under 150% limit load from the whole machine stress distribution as the working stress of the wall panel compression strength, frame edge strip compression strength, frame web compression strength and rib compression strength;

[0044] Extract the maximum shear stress under 150% limit load from the whole machine stress distribution as the working stress of the shear strength of the wall panel;

[0045] Extracting the compressive stress and shear stress under the compression-shear combined load from the whole machine stress distribution, and using the calculated results of the compressive stress and shear stress as the working stress of the compression-shear buckling of the wall panel;

[0046] Extracting the tensile stress and shear stress under the tension-shear composite load from the stress distribution of the whole machine, and using the calculated results of the tensile stress and shear stress as the working stress of the tension-shear buckling of the wall panel;

[0047] Extracting the critical buckling stress of the web from the whole machine stress distribution as the working stress of the web stability;

[0048] Extracting the maximum shear stress of the web from the stress distribution of the whole machine as the working stress of the web strength;

[0049] Extract the maximum shear stress at the connection from the whole machine stress distribution as the working stress of the connection body strength;

[0050] Extract the maximum extrusion stress at the connection from the stress distribution of the whole machine as the working stress of the strength of the connection area;

[0051] Extracting the maximum shear stress at the perforated plate from the stress distribution of the whole machine as the working stress of the perforated plate strength;

[0052] Extracting the average longitudinal normal stress at the reinforcement opening from the whole machine stress distribution as the working stress of the reinforcement opening strength;

[0053] According to the above method, the working stress of all secondary mechanical performance indicators of n primary strength indicators corresponding to the kth body structure under the jth load condition is obtained. .

[0054] In at least one embodiment of the present application, applying constraints on the whole machine virtual test finite element model includes:

[0055] Vertical constraints, pitch constraints, roll constraints, heading constraints, yaw constraints, and lateral constraints are imposed on the virtual test finite element model of the entire machine.

[0056] In at least one embodiment of the present application, in step 4, the working safety margin of the secondary mechanical performance index is calculated according to the allowable stress and the working stress, and the working safety margin is:

[0057] ;

[0058] in, is the working safety margin, is the allowable stress, For work stress.

[0059] In at least one embodiment of the present application, in step five, obtaining the design safety margin of the secondary mechanical performance index, and scoring the primary strength index according to the data correlation between the working safety margin and the design safety margin, includes:

[0060] Obtain the design safety margin of the secondary mechanical performance index ;

[0061] The design safety margin is normalized:

[0062] ;

[0063] in, is the normalized design safety margin, To provide a safety margin for the design;

[0064] The working safety margin is normalized:

[0065] ;

[0066] in, is the normalized operating safety margin, It is the working safety margin;

[0067] The first scoring factor is calculated based on the absolute difference between the normalized design safety margin and the operating safety margin:

[0068] ;

[0069] ;

[0070] in, is the absolute difference between the normalized design safety margin and the operating safety margin, is the first scoring factor, is the resolution coefficient;

[0071] The second scoring factor is calculated based on the root mean square error of the slope of the normalized design safety margin and the working safety margin, including:

[0072] Calculate the slope of the normalized design safety margin:

[0073] ;

[0074] Calculate the slope of the normalized operating safety margin:

[0075] ;

[0076] Calculate the difference in slope between the normalized design safety margin and the operating safety margin:

[0077] ;

[0078] Calculate the slope RMS error:

[0079] ;

[0080] Calculate the second scoring factor:

[0081] ;

[0082] in, is the slope of the normalized design safety margin, is the slope of the normalized working safety margin, is the slope difference between the normalized design safety margin and the working safety margin, RMSD is the root mean square error of the slope, is the second scoring factor;

[0083] The third scoring factor is calculated based on the area difference between the normalized design safety margin and the working safety margin:

[0084] ;

[0085] ;

[0086] ;

[0087] in, is the area of ​​the normalized design safety margin, is the number of the normalized design safety margin, is the area of ​​the normalized working safety margin, is the number of the normalized working safety margin, is the third scoring factor;

[0088] The score of the first-level strength index is calculated according to the first scoring factor, the second scoring factor, and the third scoring factor:

[0089] ;

[0090] in, is the score of the first-level strength index, , , is the weight coefficient.

[0091] In at least one embodiment of the present application, in step six, scoring the fuselage structure according to the primary strength index, and performing a comprehensive assessment of the static strength of the aircraft structure according to the score of the fuselage structure, including:

[0092] The k-th airframe structure and the n first-level strength indicators corresponding to the k-th airframe structure are taken as influencing factors to construct an influencing factor set:

[0093] ;

[0094] in, X is the set of influencing factors, x 1. x 2. … x n+1 For influencing factors;

[0095] According to the direct influence degree between two influencing factors, a direct influence matrix is ​​constructed:

[0096] ;

[0097] in, A To directly affect the matrix, directly affect the elements in the matrix Influencing factors x i Influencing factors x j The direct impact of

[0098] The direct impact matrix is ​​normalized to obtain the normalized direct impact matrix:

[0099] ;

[0100] ;

[0101] ;

[0102] Normalization directly affects the elements in the matrix to satisfy:

[0103] ;

[0104] ;

[0105] in, G To normalize the direct influence matrix, g ij Normalization directly affects the elements in the matrix;

[0106] Calculate the comprehensive impact matrix based on the normalized direct impact matrix:

[0107] ;

[0108] in, T is the comprehensive impact matrix, I is the identity matrix;

[0109] According to the comprehensive influence matrix, the comprehensive influence degree and comprehensive influence degree of each element in the comprehensive influence matrix are calculated respectively:

[0110] ;

[0111] ;

[0112] in, f i is the comprehensive impact, e i is the comprehensive impact degree, t ij , t ji is the element in the comprehensive impact matrix;

[0113] According to the comprehensive influence and comprehensive influence, calculate the cause degree:

[0114] ;

[0115] in, h i for the degree of cause;

[0116] Calculate the influence weight of the first-level strength index on the body structure according to the cause degree:

[0117] ;

[0118] in, is the impact weight;

[0119] According to the above method, the influence weight set of n primary strength indicators on the kth body structure is obtained:

[0120] ;

[0121] in, is the influence weight set;

[0122] Calculate the score of the kth body structure:

[0123] ;

[0124] in, is the score of the kth body structure;

[0125] A comprehensive assessment of the static strength of the aircraft structure is performed based on the score of the airframe structure.

[0126] In at least one embodiment of the present application, the method further includes step seven, scoring the whole machine according to the machine body structure, and performing a comprehensive assessment of the static strength of the whole machine according to the score of the whole machine.

[0127] The invention has at least the following beneficial technical effects:

[0128] The aircraft structure static strength comprehensive assessment method based on data correlation of the present application can provide comprehensive quantitative assessment results of the static strength of each component of the aircraft or even the entire aircraft, thereby improving the quantifiability, objectivity and accuracy of the comprehensive static strength assessment. BRIEF DESCRIPTION OF THE DRAWINGS

[0129] Figure 1 It is a flow chart of a method for comprehensive assessment of static strength of aircraft structure based on data correlation according to one embodiment of the present application;

[0130] Figure 2 It is a schematic diagram of the correspondence between the body structure and the primary strength index of an embodiment of the present application;

[0131] Figure 3 It is a schematic diagram of the correspondence between the primary strength index and the secondary mechanical performance index of an implementation method of the present application. DETAILED DESCRIPTION

[0132] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the embodiment of this application will be described in more detail below in conjunction with the drawings in the embodiment of this application. 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 this application, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be construed as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of this application are described in detail below in conjunction with the drawings.

[0133] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply 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 application.

[0134] The following is combined with Figures 1 to 3 This application is described in further detail.

[0135] This application provides a comprehensive evaluation method for static strength of aircraft structure based on data correlation, such as Figure 1 As shown, the following steps are included:

[0136] Step 1: Construct an aircraft structure static strength index system, including:

[0137] Divide the whole machine into multiple body structures;

[0138] Determine the aircraft structure static strength index corresponding to each airframe structure, the aircraft structure static strength index includes a primary strength index and a secondary mechanical performance index having a hierarchical relationship;

[0139] Step 2: quantitatively characterize the allowable stress of the secondary mechanical performance index;

[0140] Step 3: Obtain the working stress of the secondary mechanical performance index through the whole machine virtual test;

[0141] Step 4: Calculate the working safety margin of the secondary mechanical performance index based on the allowable stress and working stress;

[0142] Step 5: Obtain the design safety margin of the secondary mechanical performance index, and score the primary strength index according to the data correlation between the working safety margin and the design safety margin;

[0143] Step 6: Score the fuselage structure according to the first-level strength index, and conduct a comprehensive assessment of the static strength of the aircraft structure based on the score of the fuselage structure.

[0144] The present invention discloses a method for comprehensively evaluating the static strength of aircraft structures based on data correlation. First, in step 1, a static strength index system of aircraft structures is constructed. The whole aircraft is divided into seven airframe structures, namely: wing structure, fuselage structure, aileron structure, flap structure, elevator structure, rudder structure, bracket and landing gear structure. The static strength index of the aircraft structure corresponding to each airframe structure is determined.

[0145] Among them, Figure 2 As shown, the first-level strength indicators corresponding to the wing structure and fuselage structure include five, namely: wall panel strength, beam and rib strength, frame strength, key connection strength, opening strength; the first-level strength indicators corresponding to the aileron structure, flap structure, elevator structure and rudder structure include four, namely: wall panel strength, beam and rib strength, frame strength, key connection strength; the first-level strength indicators corresponding to the bracket and landing gear structure include: key connection strength.

[0146] like Figure 3 As shown, the secondary mechanical performance indicators corresponding to the wall panel strength include: wall panel tensile strength, wall panel compressive strength, wall panel shear strength, wall panel compression-shear buckling, wall panel tension-shear buckling; the secondary mechanical performance indicators corresponding to the beam and rib strength include: edge strip tensile strength, web stability, web strength; the secondary mechanical performance indicators corresponding to the frame strength include: frame edge strip tensile strength, frame edge strip compressive strength, frame web tensile strength, frame web compressive strength, rib tensile strength, rib compression strength; the secondary mechanical performance indicators corresponding to the key connection strength include: connection body strength, connection area strength; the secondary mechanical performance indicators corresponding to the opening strength include: opening plate strength, reinforcement mouth strength.

[0147] The comprehensive evaluation method of static strength of aircraft structure based on data correlation of the present application, secondly, in step 2, the allowable stress of the secondary mechanical performance index is quantitatively characterized, specifically including:

[0148] Determine the quantitative characterization method of the allowable stress of each secondary mechanical performance index, including:

[0149] The allowable stress of the tensile strength of the wall panel, the tensile strength of the edge strip, the tensile strength of the frame edge strip, the tensile strength of the frame web and the tensile strength of the ribs is quantitatively characterized by the tensile limit stress;

[0150] The allowable stress of the wall plate compression strength, frame edge strip compression strength, frame web compression strength and rib compression strength is quantitatively characterized by compression loss stress;

[0151] The allowable stress of the wall plate shear strength and web plate strength is quantitatively characterized by the shear limit stress;

[0152] The allowable stresses of wall plate compression shear buckling, wall plate tension shear buckling and web stability are quantitatively characterized by critical buckling stress.

[0153] The allowable stress of the connection body strength and the perforated plate strength is quantitatively characterized by the maximum allowable shear stress;

[0154] The allowable stress of the connection zone strength is quantitatively characterized by the extrusion stress;

[0155] The allowable stress of the reinforcement mouth strength is quantitatively characterized by the average longitudinal normal stress;

[0156] According to the quantitative representation of the allowable stress of each secondary mechanical performance index, the allowable stress of each secondary mechanical performance index is calculated by theoretical formula;

[0157] According to the above method, the allowable stress of all secondary mechanical performance indicators of the n first-level strength indicators corresponding to the k-th fuselage structure under the j-th load condition is obtained. .

[0158] The aircraft structure static strength comprehensive assessment method based on data correlation of the present application, in step 3, obtains the working stress of the secondary mechanical performance index through the whole machine virtual test, including the following steps:

[0159] Constructing a finite element model of the whole machine virtual test, which should include detailed modeling of each body structure obtained by dividing the whole machine in step 1;

[0160] Apply constraints on the virtual test finite element model of the whole machine; in the preferred embodiment of the present application, the constraints are arranged as follows: the vertical displacement of the front landing gear, left main landing gear and right main landing gear of the virtual test finite element model of the whole machine is constrained, and these three constraints provide vertical constraint, pitch constraint and roll constraint respectively, and a support point is arranged in the heading of the left main landing gear and the right main landing gear respectively, which can provide heading constraint and yaw constraint, and lateral constraint is arranged on the left main landing gear.

[0161] The load application points are arranged on the finite element model of the whole machine virtual test, and the load is applied at the load application points, gradually increasing from the initial load to 150% of the limit load, and the stress distribution of the whole machine under the jth load condition is obtained respectively; in this embodiment, the final load application point of the model is set according to the position of the tape of the whole machine virtual test.

[0162] The tensile limit stress under 150% limiting load is extracted from the whole machine stress distribution as the working stress of the wall plate tensile strength, edge strip tensile strength, frame edge strip tensile strength, frame web tensile strength and rib tensile strength;

[0163] The compressive limit stress under 150% limit load is extracted from the whole machine stress distribution as the working stress of the wall plate compression strength, frame edge strip compression strength, frame web compression strength and rib compression strength;

[0164] The maximum shear stress under 150% limit load is extracted from the whole machine stress distribution as the working stress of the wall panel shear strength;

[0165] Extract the compressive stress and shear stress under the compression-shear combined load from the whole machine stress distribution, and use the calculated results of the compressive stress and shear stress as the working stress of the compression-shear buckling of the wall panel;

[0166] In this embodiment, = , is the compressive stress, is the shear stress, is the calculation result of compressive stress and shear stress;

[0167] Extract the tensile stress and shear stress under the tension-shear composite load from the stress distribution of the whole machine, and use the calculated results of the tensile stress and shear stress as the working stress of the tension-shear buckling of the wall panel;

[0168] In this embodiment, = , is the tensile stress, is the shear stress, is the calculation result of tensile stress and shear stress;

[0169] The critical buckling stress of the web is extracted from the stress distribution of the whole machine as the working stress of the web stability;

[0170] The maximum shear stress of the web is extracted from the stress distribution of the whole machine as the working stress of the web strength;

[0171] The maximum shear stress at the connection is extracted from the stress distribution of the whole machine as the working stress of the connection body strength;

[0172] The maximum extrusion stress at the connection is extracted from the stress distribution of the whole machine as the working stress of the connection area strength;

[0173] The maximum shear stress at the perforated plate is extracted from the stress distribution of the whole machine as the working stress of the perforated plate strength;

[0174] The average longitudinal normal stress at the reinforcement mouth is extracted from the stress distribution of the whole machine as the working stress of the reinforcement mouth strength;

[0175] According to the above method, the working stress of all secondary mechanical performance indicators of n primary strength indicators corresponding to the kth body structure under the jth load condition is obtained. .

[0176] In the present invention, the aircraft structure static strength comprehensive assessment method based on data correlation, in step 4, the working safety margin of the secondary mechanical performance index is calculated according to the allowable stress and the working stress. The working safety margin is:

[0177] ;

[0178] in, is the working safety margin, is the allowable stress, For work stress.

[0179] According to the above method, the working safety margins of all secondary mechanical performance indicators of n primary strength indicators corresponding to the kth fuselage structure under the jth load condition are calculated, which can quantify all secondary mechanical performance indicators and eliminate the influence of dimensions.

[0180] The aircraft structure static strength comprehensive assessment method based on data correlation of the present application, in step 5, obtains the design safety margin of the secondary mechanical performance index, and scores the primary strength index according to the data correlation between the working safety margin and the design safety margin, including the following steps:

[0181] Obtaining the design safety margin of secondary mechanical performance indicators ;

[0182] Generally, the aircraft designer provides the design safety margins corresponding to all secondary mechanical performance indicators.

[0183] Normalize the design safety margin:

[0184] ;

[0185] in, is the normalized design safety margin, To provide a safety margin for the design;

[0186] Normalize the working safety margin:

[0187] ;

[0188] in, is the normalized operating safety margin, It is the working safety margin;

[0189] Taking the design safety margin as the reference value and the working safety margin as the comparison value, a multi-correlation comprehensive data correlation comparison method is proposed using the idea of ​​grey correlation. The data correlation between the normalized design safety margin and the working safety margin of all secondary mechanical performance indicators is compared, and a comprehensive scoring evaluation is performed on the primary strength indicators based on the data correlation.

[0190] Specifically:

[0191] The first scoring factor is calculated based on the absolute difference between the normalized design safety margin and the operating safety margin:

[0192] ;

[0193] ;

[0194] in, is the absolute difference between the normalized design safety margin and the operating safety margin, is the first scoring factor, is the resolution coefficient;

[0195] The second scoring factor is calculated based on the root mean square error of the slope of the normalized design safety margin and the working safety margin, including:

[0196] Calculate the slope of the normalized design safety margin:

[0197] ;

[0198] Calculate the slope of the normalized operating safety margin:

[0199] ;

[0200] Calculate the difference in slope between the normalized design safety margin and the operating safety margin:

[0201] ;

[0202] Calculate the slope RMS error:

[0203] ;

[0204] Calculate the second scoring factor:

[0205] ;

[0206] in, is the slope of the normalized design safety margin, is the slope of the normalized working safety margin, is the slope difference between the normalized design safety margin and the working safety margin, RMSD is the root mean square error of the slope, is the second scoring factor;

[0207] The third scoring factor is calculated based on the area difference between the normalized design safety margin and the working safety margin:

[0208] ;

[0209] ;

[0210] ;

[0211] in, is the area of ​​the normalized design safety margin, is the number of the normalized design safety margin, is the area of ​​the normalized working safety margin, is the number of the normalized working safety margin, is the third scoring factor;

[0212] According to the first scoring factor, the second scoring factor and the third scoring factor, the score of the first-level strength index is calculated:

[0213] ;

[0214] in, is the score of the first-level strength index, , , is the weight coefficient, and the average weight can be used.

[0215] The score interval of the first-level strength index calculated by the above method is [0, 100].

[0216] In this embodiment, the overall correlation of the data is taken into account, and the overall deviation is measured by the absolute difference between the normalized design safety margin and the working safety margin to evaluate the overall similarity; the slope correlation of the data is considered, and the root mean square error of the slopes of the normalized design safety margin and the working safety margin is used to measure the similarity of the changing trend based on the difference between the error and the maximum slope difference; the area correlation of the data is considered, and the area of ​​the curve is calculated by the trapezoidal rule, and the similarity between the two is measured based on the area difference between the normalized design safety margin and the working safety margin.

[0217] The aircraft structure static strength comprehensive assessment method based on data correlation of the present application, in step 6, scores the fuselage structure according to the primary strength index, and performs a comprehensive assessment of the aircraft structure static strength according to the score of the fuselage structure, including the following steps:

[0218] According to the correspondence between the airframe structure and the first-level strength index, the k-th airframe structure and the n first-level strength indexes corresponding to the k-th airframe structure are taken as influencing factors to construct the influencing factor set:

[0219] ;

[0220] in, X is the set of influencing factors, x 1. x 2. … x n+1 For influencing factors;

[0221] The direct influence relationship between different first-level strength indicators and their influence on the body structure are analyzed to obtain the direct influence degree between two influencing factors;

[0222] According to the direct influence degree between two influencing factors, a direct influence matrix is ​​constructed:

[0223] ;

[0224] in, A To directly affect the matrix, directly affect the elements in the matrix Influencing factors x i Influencing factors x j The direct influence of the influencing factor on itself is 0, that is, when i=j ;

[0225] The direct impact matrix is ​​normalized to obtain the normalized direct impact matrix:

[0226] ;

[0227] ;

[0228] ;

[0229] Normalization directly affects the elements in the matrix to satisfy:

[0230] ;

[0231] ;

[0232] in, G To normalize the direct influence matrix, g ij Normalization directly affects the elements in the matrix;

[0233] Calculate the comprehensive impact matrix based on the normalized direct impact matrix:

[0234] ;

[0235] in, T is the comprehensive impact matrix, I is the identity matrix;

[0236] because ,when hour, , ;

[0237] The comprehensive impact matrix represents the superposition of direct and indirect impacts between influencing factors to determine the comprehensive impact of lower-level factors on upper-level factors;

[0238] According to the comprehensive influence matrix, the comprehensive influence degree and comprehensive influence degree of each element in the comprehensive influence matrix are calculated respectively:

[0239] ;

[0240] ;

[0241] in, f i is the comprehensive impact, e i is the comprehensive impact degree, t ij , t ji is the element in the comprehensive impact matrix;

[0242] The comprehensive influence degree represents the influence degree of the influencing factor on other influencing factors in the influencing factor set, and the comprehensive impact degree represents the influence degree of other influencing factors in the affected factor set of the influencing factor;

[0243] According to the comprehensive influence and comprehensive influence, calculate the cause degree:

[0244] ;

[0245] in, h i for the degree of cause;

[0246] The difference between the comprehensive influence degree and the comprehensive influence degree is the causal degree, which represents the causal logical relationship between the influencing factor and other influencing factors. If the causal degree of the body structure is negative, it means that the influencing factor is greatly affected by other influencing factors. If the causal degree of the first-level strength index is positive, it means that the influencing factor has a great influence on other influencing factors.

[0247] The sum of comprehensive influence and comprehensive influence is the centrality:

[0248] ;

[0249] in, m i is the centrality;

[0250] The centrality represents the importance of the influencing factor in the influencing factor set. The larger the centrality, the higher the importance of the influencing factor.

[0251] Extract the cause degree of all first-level strength indicators, and calculate the influence weight of the first-level strength indicators on the body structure according to the normalized cause degree:

[0252] ;

[0253] in, is the impact weight;

[0254] According to the above method, the influence weight set of n primary strength indicators on the kth body structure is obtained:

[0255] ;

[0256] in, is the influence weight set;

[0257] Calculate the score of the kth body structure:

[0258] ;

[0259] in, is the score of the kth body structure;

[0260] The static strength of the aircraft structure is comprehensively assessed based on the score of the airframe structure.

[0261] The evaluation scores of all the airframe structures are obtained according to the above method, thereby achieving a comprehensive quantitative assessment of the static strength of each airframe structure.

[0262] The aircraft structure static strength comprehensive assessment method based on data correlation of the present application also includes step seven, scoring the whole aircraft according to the fuselage structure, and conducting a comprehensive assessment of the static strength of the whole aircraft according to the score of the whole aircraft.

[0263] It can be understood that, referring to step six, the airframe structure is replaced by the whole machine, and the first-level strength index is replaced by the airframe structure, and the score of the whole machine is obtained using the same method, thereby achieving a comprehensive quantitative assessment of the static strength of the whole machine.

[0264] The aircraft structure static strength comprehensive assessment method based on data correlation of the present application adopts a step-by-step quantification method to process the aircraft static strength allowable data and the whole machine virtual test work data, comprehensively scores and evaluates the primary strength index through a multi-correlation comprehensive data correlation comparison method, and comprehensively scores and evaluates the fuselage structure through a multi-level influence analysis weighting method. A static strength comprehensive evaluation model that can evaluate different aircraft structures is constructed, which can provide the static strength comprehensive quantitative assessment results of each aircraft component and even the whole aircraft, thereby improving the quantifiability, objectivity and accuracy of the static strength comprehensive assessment.

[0265] The aircraft structure static strength comprehensive assessment method based on data correlation in this application can assist in aircraft airworthiness and compliance verification, provide objective data reference for aircraft structure selection, and provide decision-making basis for aircraft finalization and identification, which helps to improve the model development process.

[0266] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for comprehensive assessment of static strength of aircraft structure based on data correlation, characterized in that: include: Step 1: Construct an aircraft structure static strength index system, including: Divide the whole machine into multiple body structures; Determining the aircraft structure static strength index corresponding to each of the fuselage structures, wherein the aircraft structure static strength index includes a primary strength index and a secondary mechanical performance index having a hierarchical relationship; Step 2: quantitatively characterize the allowable stress of the secondary mechanical performance index; Step 3: obtaining the working stress of the secondary mechanical performance index through a whole machine virtual test; Step 4: Calculate the working safety margin of the secondary mechanical performance index according to the allowable stress and the working stress; Step 5: obtaining the design safety margin of the secondary mechanical performance index, and scoring the primary strength index according to the data correlation between the working safety margin and the design safety margin, including: Obtain the design safety margin [MS] of the secondary mechanical performance index nj ; The design safety margin is normalized to obtain a normalized design safety margin ref i ; The working safety margin is normalized to obtain a normalized working safety margin comp i ; The first scoring factor is calculated based on the absolute difference between the normalized design safety margin and the operating safety margin: Among them, diff i is the absolute difference between the normalized design safety margin and the operating safety margin, is the first scoring factor, ρ is the resolution coefficient; The second scoring factor is calculated based on the root mean square error of the slope of the normalized design safety margin and the working safety margin, including: Calculate the slope of the normalized design safety margin; Calculate the slope of the normalized working safety margin; Calculate the slope difference diff between the normalized design safety margin and the working safety margin slopei ; Calculate the slope root mean square error RMSD; Calculate the second scoring factor: Among them, diff slopei is the slope difference between the normalized design safety margin and the working safety margin, RMSD is the root mean square error of the slope, is the second scoring factor; The third scoring factor is calculated based on the area difference between the normalized design safety margin and the working safety margin: in, is the area of ​​the normalized design safety margin, r is the number of the normalized design safety margin, is the area of ​​the normalized working safety margin, c is the number of the normalized working safety margin, ξ areai is the third scoring factor; The score of the first-level strength index is calculated according to the first scoring factor, the second scoring factor, and the third scoring factor: Among them, ξ total is the score of the first-level strength index, λ1, λ2, λ3 are weight coefficients; Step 6: Score the fuselage structure according to the first-level strength index, and conduct a comprehensive assessment of the static strength of the aircraft structure based on the score of the fuselage structure.

2. The method for comprehensive assessment of static strength of aircraft structure based on data correlation according to claim 1 is characterized in that: In step 1, the whole machine is divided into multiple body structures, including: Dividing the whole aircraft into multiple fuselage structures, the fuselage structure includes: wing structure, fuselage structure, aileron structure, flap structure, elevator structure, rudder structure, bracket and landing gear structure; Determining the aircraft structure static strength index corresponding to each of the fuselage structures includes: The first-level strength indicators corresponding to the wing structure and the fuselage structure include: panel strength, beam and rib strength, frame strength, key connection strength, and opening strength; The first-level strength indicators corresponding to the aileron structure, the flap structure, the elevator structure and the rudder structure include: wall panel strength, beam and rib strength, frame strength, and key connection strength; The first-level strength indicators corresponding to the bracket and landing gear structure include: key connection strength; The secondary mechanical performance indicators corresponding to the wall panel strength include: wall panel tensile strength, wall panel compression strength, wall panel shear strength, wall panel compression shear buckling, wall panel tension shear buckling; The secondary mechanical performance indicators corresponding to the beam and rib strength include: flange tensile strength, web stability, and web strength; The secondary mechanical performance indicators corresponding to the frame strength include: frame edge strip tensile strength, frame edge strip compression strength, frame web tensile strength, frame web compression strength, rib tensile strength, rib compression strength; The secondary mechanical performance indicators corresponding to the key connection strength include: connection body strength and connection area strength; The secondary mechanical performance indicators corresponding to the opening strength include: opening plate strength and reinforcement opening strength.

3. The method for comprehensive assessment of static strength of aircraft structure based on data correlation according to claim 2 is characterized in that: In step 2, the allowable stress of the secondary mechanical performance index is quantitatively characterized, including: The quantitative characterization method for determining the allowable stress of each of the secondary mechanical performance indicators includes: The allowable stress of the wall panel tensile strength, the edge strip tensile strength, the frame edge strip tensile strength, the frame web tensile strength and the rib tensile strength is quantitatively characterized by using the tensile limit stress; The allowable stress of the wall panel compression strength, the frame edge strip compression strength, the frame web compression strength and the rib compression strength is quantitatively characterized by compression loss stress; The allowable stress of the wall plate shear strength and the web plate strength is quantitatively characterized by the shear limit stress; The allowable stresses of the wall plate compression shear buckling, the wall plate tension shear buckling and the web plate stability are quantitatively characterized by using the critical buckling stress; The allowable stress of the connection body strength and the perforated plate strength is quantitatively characterized by the maximum allowable shear stress; The allowable stress of the connection zone strength is quantitatively characterized by extrusion stress; The allowable stress of the reinforcement mouth strength is quantitatively characterized by the average longitudinal normal stress; According to the quantitative representation method of the allowable stress of each of the secondary mechanical performance indicators, the allowable stress of each of the secondary mechanical performance indicators is calculated by a theoretical formula; According to the above method, the allowable stress [σ] of all secondary mechanical performance indicators of the n primary strength indicators corresponding to the kth fuselage structure under the jth load condition is obtained. nj .

4. The method for comprehensive assessment of static strength of aircraft structure based on data correlation according to claim 3 is characterized in that: In step three, the working stress of the secondary mechanical performance index is obtained through a whole machine virtual test, including: Construct a finite element model for virtual testing of the entire machine; Applying constraints on the whole machine virtual test finite element model; Arranging load application points on the whole machine virtual test finite element model, applying loads at the load application points, gradually increasing the load from the initial load to 150% of the limit load, and obtaining the whole machine stress distribution under the jth load condition respectively; Extract the tensile limit stress under 150% limit load from the whole machine stress distribution as the working stress of the wall panel tensile strength, the edge strip tensile strength, the frame edge strip tensile strength, the frame web tensile strength and the rib tensile strength; Extract the compressive limit stress under 150% limit load from the whole machine stress distribution as the working stress of the wall panel compression strength, frame edge strip compression strength, frame web compression strength and rib compression strength; Extract the maximum shear stress under 150% limit load from the whole machine stress distribution as the working stress of the shear strength of the wall panel; Extracting the compressive stress and shear stress under the compression-shear combined load from the whole machine stress distribution, and using the calculated results of the compressive stress and shear stress as the working stress of the compression-shear buckling of the wall panel; Extracting the tensile stress and shear stress under the tension-shear composite load from the stress distribution of the whole machine, and using the calculated results of the tensile stress and shear stress as the working stress of the tension-shear buckling of the wall panel; Extracting the critical buckling stress of the web from the whole machine stress distribution as the working stress of the web stability; Extracting the maximum shear stress of the web from the stress distribution of the whole machine as the working stress of the web strength; Extract the maximum shear stress at the connection from the whole machine stress distribution as the working stress of the connection body strength; Extract the maximum extrusion stress at the connection from the stress distribution of the whole machine as the working stress of the strength of the connection area; Extracting the maximum shear stress at the perforated plate from the stress distribution of the whole machine as the working stress of the perforated plate strength; Extracting the average longitudinal normal stress at the reinforcement opening from the whole machine stress distribution as the working stress of the reinforcement opening strength; According to the above method, the working stress σ of all secondary mechanical performance indicators of the n first-level strength indicators corresponding to the k-th fuselage structure under the j-th load condition is obtained: nj .

5. The method for comprehensive assessment of static strength of aircraft structure based on data correlation according to claim 4 is characterized in that: Imposing constraints on the whole machine virtual test finite element model includes: Vertical constraints, pitch constraints, roll constraints, heading constraints, yaw constraints, and lateral constraints are imposed on the virtual test finite element model of the entire machine.

6. The method for comprehensive assessment of static strength of aircraft structure based on data correlation according to claim 5 is characterized in that: In step 4, the working safety margin of the secondary mechanical performance index is calculated according to the allowable stress and the working stress, and the working safety margin is: MS nj =[s] nj / s nj -1 Among them, MS nj is the operating safety margin, [σ] nj is the allowable stress, σ nj For work stress.

7. The method for comprehensive assessment of aircraft structure static strength based on data correlation according to claim 6, characterized in that: In step 6, the fuselage structure is scored according to the first-level strength index, and a comprehensive assessment of the static strength of the aircraft structure is performed according to the score of the fuselage structure, including: The k-th airframe structure and the n first-level strength indicators corresponding to the k-th airframe structure are taken as influencing factors to construct an influencing factor set: X={x1,x2,...,x n+1 } Among them, X is the influencing factor set, x1, x2, ..., x n+1 For influencing factors; According to the direct influence degree between two influencing factors, a direct influence matrix is ​​constructed: Among them, A is the direct influence matrix, and the element a in the direct influence matrix ij Influencing factor x i Influencing factors x j The direct impact of The direct impact matrix is ​​normalized to obtain the normalized direct impact matrix: 1≤i≤n+1 1≤j≤n+1 Normalization directly affects the elements in the matrix to satisfy: 0≤g ij ≤1 Among them, G is the normalized direct influence matrix, g ij Normalization directly affects the elements in the matrix; Calculate the comprehensive impact matrix based on the normalized direct impact matrix: Among them, T is the comprehensive influence matrix, I is the unit matrix; According to the comprehensive influence matrix, the comprehensive influence degree and comprehensive influence degree of each element in the comprehensive influence matrix are calculated respectively: Among them, f i is the comprehensive impact, e i is the comprehensive impact degree, t ij ,t ji is the element in the comprehensive impact matrix; According to the comprehensive influence and comprehensive influence, calculate the cause degree: h i =f i -e i Among them, h i for the degree of cause; Calculate the influence weight of the first-level strength index on the body structure according to the cause degree: Among them, w i is the impact weight; According to the above method, the influence weight set of n primary strength indicators on the kth body structure is obtained: IN k ={w1,w2,...,w n } Among them, W k is the influence weight set; Calculate the score of the kth body structure: Among them, Score k is the score of the kth body structure; A comprehensive assessment of the static strength of the aircraft structure is performed based on the score of the airframe structure.

8. The method for comprehensive assessment of static strength of aircraft structure based on data correlation according to claim 7 is characterized in that: The method further comprises step seven, scoring the whole machine according to the machine body structure, and conducting a comprehensive evaluation of the static strength of the whole machine according to the score of the whole machine.

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