A method for determining the adaptive cohesive zone model of propellants

Abstract

The invention discloses a method for determining a propellant adaptive cohesive zone model, which belongs to the technical fields of experimental mechanics and computational fracture mechanics. The method comprises: using a first propellant test piece and a second propellant test piece to carry out a constant speed tensile test, obtaining a cohesive strength reference value and a cohesive energy reference value of the propellant adaptive cohesive zone model; based on the cohesive strength reference value and the cohesive energy reference value of the propellant adaptive cohesive zone model, setting the propellant adaptive cohesive zone model as a linear reduction model; based on the maximum separation displacement of the linear reduction model, setting control points on the linear reduction model; based on the test results of the constant speed tensile test of the second propellant test piece, inversely calculating the cohesive force corresponding to each control point; based on each control point and its corresponding cohesive force, obtaining the propellant adaptive cohesive zone model. The method can get rid of the influence of the traditional cohesive zone curve model on the research of the propellant cohesive zone model.

Description

Technical Field

[0001] The invention relates to a method for determining a propellant self-adaptive cohesive zone model, and belongs to the technical field of experimental mechanics and computational fracture mechanics. Background Art

[0002] Existing research on cohesion zone models often relies on existing curve configurations, such as the classic bilinear model, trapezoidal model, and bilinear model.

[0003] In order to get rid of the influence of the traditional cohesive zone curve model on the research of propellant cohesive zone model, it is urgent to develop a propellant adaptive cohesive zone model without fixed shape. Summary of the invention

[0004] The purpose of the present invention is to provide a method for determining a propellant self-adaptive cohesive zone model, which can get rid of the influence of a traditional cohesive zone curve model on the research of the propellant cohesive zone model.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for determining a propellant adaptive cohesive zone model, comprising:

[0007] A constant-speed tensile test was carried out using the first propellant test piece to obtain a reference value of the cohesive strength of the propellant adaptive cohesive zone model;

[0008] A constant-speed tensile test was carried out using the second propellant test piece to obtain the cohesive energy reference value of the propellant adaptive cohesive zone model;

[0009] Based on the cohesive strength reference value and cohesive energy reference value of the propellant adaptive cohesive zone model, the propellant adaptive cohesive zone model is set as a linear reduction model, and the maximum separation displacement of the linear reduction model is calculated;

[0010] Setting control points on the linear reduction model based on the maximum separation displacement of the linear reduction model;

[0011] Based on the test results of the constant speed tensile test of the second propellant test piece, the cohesive force corresponding to each control point is inversely calculated;

[0012] Based on each control point and its corresponding cohesive force, a propellant adaptive cohesive zone model is obtained.

[0013] In combination with the first aspect, further, the first propellant test piece is a dumbbell-shaped propellant test piece; and the second propellant test piece is a Type I propellant test piece.

[0014] In combination with the first aspect, further, a constant speed tensile test is carried out using the first propellant test piece to obtain a cohesive strength reference value of the propellant adaptive cohesive zone model, including:

[0015] Conducting a constant speed tensile test using the first propellant test piece to obtain a force-displacement curve of the first propellant test piece;

[0016] The cohesive strength reference value of the propellant adaptive cohesive zone model is calculated based on the maximum value of the force in the force-displacement curve of the first propellant test piece and the cross-sectional area of ​​the first propellant test piece.

[0017] In combination with the first aspect, further, the calculation formula of the cohesive strength reference value of the propellant adaptive cohesive zone model is:

[0018] ;

[0019] in, represents the cohesive strength reference value of the propellant adaptive cohesive zone model, represents the maximum value of the force in the force-displacement curve of the first propellant test piece, represents the cross-sectional area of ​​the first propellant test piece.

[0020] In combination with the first aspect, further, a constant speed tensile test is carried out using the second propellant test piece to obtain a cohesive energy reference value of the propellant adaptive cohesive zone model, including:

[0021] Conducting a constant speed tensile test using the second propellant test piece to obtain a force-displacement curve of the second propellant test piece;

[0022] The cohesive energy reference value of the propellant adaptive cohesive zone model is calculated based on the area enclosed by the force-displacement curve of the second propellant test piece and the coordinate axis, as well as the thickness of the second propellant test piece and the maximum value of the crack extension displacement.

[0023] In combination with the first aspect, further, the calculation formula of the cohesive energy reference value of the propellant adaptive cohesive zone model is:

[0024] ;

[0025] in, represents the cohesive energy reference value of the propellant adaptive cohesive zone model, represents the area enclosed by the force-displacement curve of the second propellant test piece and the coordinate axis, represents the thickness of the second propellant test piece, represents the maximum value of the crack extension displacement of the second propellant test piece, where represents the width of the second propellant test piece, Indicates the preset crack initiation length of the second propellant test piece.

[0026] In combination with the first aspect, further, based on the cohesive strength reference value and the cohesive energy reference value of the propellant adaptive cohesive zone model, the propellant adaptive cohesive zone model is set as a linear reduction model, and the maximum separation displacement of the linear reduction model is calculated, including:

[0027] The cohesive strength reference value of the propellant adaptive cohesive zone model is used as the vertical intercept of the linear reduction model, and the cohesive energy reference value of the propellant adaptive cohesive zone model is used as the area enclosed by the linear reduction model and the coordinate axis.

[0028] Based on the longitudinal intercept of the linear reduction model and the area enclosed by it and the coordinate axis, the transverse intercept of the linear reduction model, that is, the maximum separation displacement of the linear reduction model, is calculated.

[0029] In combination with the first aspect, further, based on the maximum separation displacement of the linear reduction model, setting the control point on the linear reduction model includes:

[0030] The maximum separation displacement of the linear reduction model is equally divided;

[0031] According to the horizontal coordinates corresponding to each equally divided point, control points are set on the linear reduction model.

[0032] In combination with the first aspect, further, based on the test results of the constant speed tensile test of the second propellant test piece, the inverse calculation of the cohesive force corresponding to each control point includes:

[0033] Based on the force-displacement curve of the second propellant test piece, the cohesive force corresponding to each control point is inversely calculated using the finite element calculation model.

[0034] In combination with the first aspect, further, based on each control point and its corresponding cohesive force, obtaining a propellant adaptive cohesive zone model includes:

[0035] Based on the cohesion corresponding to each control point, the ordinate of each control point is updated to obtain a new control point;

[0036] Connect the new control points to form a propellant adaptive cohesive zone model.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The method for determining a propellant adaptive cohesive zone model provided by the present invention obtains a cohesive strength reference value and a cohesive energy reference value of the propellant adaptive cohesive zone model by performing a constant-speed tensile test on a first propellant test piece and a second propellant test piece, and then sets the propellant adaptive cohesive zone model as a linear reduction model. Based on the maximum separation displacement of the linear reduction model, control points are set on the linear reduction model, and the cohesive force corresponding to each control point is calculated by inversion to obtain the propellant adaptive cohesive zone model. The method can get rid of the influence of the traditional cohesive zone curve model on the research of the propellant cohesive zone model. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of the geometric dimensions of a dumbbell-shaped propellant test piece provided in an embodiment of the present invention;

[0040] Figure 2 is a schematic diagram of a force-displacement curve of a dumbbell-shaped propellant test piece provided in an embodiment of the present invention;

[0041] Figure 3 is a schematic diagram of a Type I propellant test piece provided in an embodiment of the present invention;

[0042] Figure 4 is a schematic diagram of a linear reduction model provided by an embodiment of the present invention;

[0043] Figure 5 It is a schematic diagram of a propellant adaptive cohesive zone model provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The technical solution of the present application is further described in detail below in conjunction with specific implementation methods.

[0045] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as limitations on the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments may be combined with each other.

[0046] Embodiment 1:

[0047] This embodiment provides a method for determining a propellant adaptive cohesive zone model, which specifically includes the following steps:

[0048] Step 1: Conduct a constant speed tensile test using the first propellant test piece to obtain a reference value of the cohesive strength of the propellant adaptive cohesive zone model;

[0049] In this embodiment, the constant speed tensile test is carried out using the first propellant test piece to obtain the cohesive strength reference value of the propellant adaptive cohesive zone model, which specifically includes the following steps:

[0050] Step 1: Conduct a constant speed tensile test using the first propellant test piece to obtain a force-displacement curve of the first propellant test piece;

[0051] Step 2: Based on the maximum value of the force in the force-displacement curve of the first propellant test piece and the cross-sectional area of ​​the first propellant test piece, the cohesive strength reference value of the propellant adaptive cohesive zone model is calculated.

[0052] In this embodiment, the calculation formula of the cohesive strength reference value of the propellant adaptive cohesive zone model is:

[0053] ;

[0054] in, represents the cohesive strength reference value of the propellant adaptive cohesive zone model, represents the maximum value of the force in the force-displacement curve of the first propellant test piece, represents the cross-sectional area of ​​the first propellant test piece.

[0055] Step 2: Conduct a constant speed tensile test using the second propellant test piece to obtain a reference value of the cohesive energy of the propellant adaptive cohesive zone model;

[0056] In this embodiment, the constant speed tensile test is carried out using the second propellant test piece to obtain the cohesive energy reference value of the propellant adaptive cohesive zone model, which specifically includes the following steps:

[0057] Step 1: Conduct a constant speed tensile test using the second propellant test piece to obtain a force-displacement curve of the second propellant test piece;

[0058] Step 2: Based on the area enclosed by the force-displacement curve of the second propellant test piece and the coordinate axis, as well as the thickness of the second propellant test piece and the maximum value of the crack extension displacement, calculate the cohesive energy reference value of the propellant adaptive cohesive zone model.

[0059] In this embodiment, the calculation formula of the cohesive energy reference value of the propellant adaptive cohesive zone model is:

[0060] ;

[0061] in, represents the cohesive energy reference value of the propellant adaptive cohesive zone model, represents the area enclosed by the force-displacement curve of the second propellant test piece and the coordinate axis, represents the thickness of the second propellant test piece, represents the maximum value of the crack extension displacement of the second propellant test piece, where represents the width of the second propellant test piece, Indicates the preset crack initiation length of the second propellant test piece.

[0062] Step 3: Based on the cohesive strength reference value and the cohesive energy reference value of the propellant adaptive cohesive zone model, the propellant adaptive cohesive zone model is set as a linear reduction model, and the maximum separation displacement of the linear reduction model is calculated;

[0063] In this embodiment, based on the cohesive strength reference value and the cohesive energy reference value of the propellant adaptive cohesive zone model, the propellant adaptive cohesive zone model is set as a linear reduction model, and the maximum separation displacement of the linear reduction model is calculated, which specifically includes the following steps:

[0064] Step 1: The cohesive strength reference value of the propellant adaptive cohesive zone model is used as the vertical intercept of the linear reduction model, and the cohesive energy reference value of the propellant adaptive cohesive zone model is used as the area enclosed by the linear reduction model and the coordinate axis;

[0065] Step 2: Based on the vertical intercept of the linear reduction model and the area enclosed by it and the coordinate axis, calculate the horizontal intercept of the linear reduction model, that is, the maximum separation displacement of the linear reduction model.

[0066] Step 4: Based on the maximum separation displacement of the linear reduction model, set the control points on the linear reduction model;

[0067] In this embodiment, based on the maximum separation displacement of the linear reduction model, setting the control point on the linear reduction model specifically includes the following steps:

[0068] Step 1: Divide the maximum separation displacement of the linear reduction model into equal parts;

[0069] Step 2: Set control points on the linear reduction model according to the horizontal coordinates corresponding to each equally divided point.

[0070] Step 5: Based on the test results of the constant speed tensile test of the second propellant test piece, inversely calculate the cohesive force corresponding to each control point;

[0071] In this embodiment, based on the test results of the constant-speed tensile test of the second propellant test piece, when the cohesive force corresponding to each control point is inversely calculated, the cohesive force corresponding to each control point is inversely calculated using a finite element calculation model based on the force-displacement curve of the second propellant test piece.

[0072] Step 6: Based on each control point and its corresponding cohesive force, obtain the propellant adaptive cohesive zone model.

[0073] In this embodiment, based on each control point and its corresponding cohesive force, obtaining the propellant adaptive cohesive zone model specifically includes the following steps:

[0074] Step 1: Based on the cohesion corresponding to each control point, the ordinate of each control point is updated to obtain a new control point;

[0075] Step 2: Connect the new control points to form a propellant adaptive cohesive zone model.

[0076] The method for determining the propellant adaptive cohesive zone model provided in the present embodiment obtains the cohesive strength reference value and the cohesive energy reference value of the propellant adaptive cohesive zone model by performing a constant-speed tensile test on the first propellant test piece and the second propellant test piece, and then sets the propellant adaptive cohesive zone model as a linear reduction model. Based on the maximum separation displacement of the linear reduction model, control points are set on the linear reduction model, and the cohesive force corresponding to each control point is calculated by inversion to obtain the propellant adaptive cohesive zone model. This method can get rid of the influence of the traditional cohesive zone curve model on the research of the propellant cohesive zone model.

[0077] Embodiment 2:

[0078] This embodiment provides a method for determining a propellant adaptive cohesive zone model. Based on Embodiment 1, the first propellant test piece is a dumbbell-shaped propellant test piece, and the second propellant test piece is a Type I propellant test piece. The method specifically includes the following steps:

[0079] Step 1: Conduct a constant speed tensile test using a dumbbell-shaped propellant test piece to obtain a reference value of the cohesive strength of the propellant adaptive cohesive zone model;

[0080] In this embodiment, Figure 1 As shown, the dumbbell-shaped propellant test piece has a length of 120 mm, a width of 25 ± 0.5 mm, a thickness of 10 ± 0.5 mm, a middle portion length of 70 ± 0.5 mm, a middle portion width of 10 ± 0.5 mm, and a radius of a quarter arc of the middle portion of 12 ± 0.2 mm.

[0081] The constant speed tensile test is carried out using a dumbbell-shaped propellant test piece to obtain the cohesive strength reference value of the propellant adaptive cohesive zone model, which specifically includes the following steps:

[0082] Step 1: Conduct a constant speed tensile test using a dumbbell-shaped propellant test piece to obtain a force-displacement curve of the dumbbell-shaped propellant test piece;

[0083] In this embodiment, a constant speed tensile test is carried out using a dumbbell-type propellant test piece to obtain a force-displacement curve of the dumbbell-type propellant test piece. Figure 2 As shown, Figure 2 middle, It represents the maximum force in the force-displacement curve of the dumbbell-shaped propellant test piece.

[0084] Step 2: Based on the maximum force in the force-displacement curve of the dumbbell-shaped propellant test piece and the cross-sectional area of ​​the dumbbell-shaped propellant test piece, calculate the cohesive strength reference value of the propellant adaptive cohesive zone model.

[0085] Step 2: Conduct a constant speed tensile test using a Type I propellant test piece to obtain a reference value of the cohesive energy of the propellant's adaptive cohesive zone model;

[0086] In this embodiment, Figure 3 As shown, the width of the Type I propellant test piece is , the initial crack length is preset to .

[0087] The constant speed tensile test is carried out using a Type I propellant test piece to obtain the cohesive energy reference value of the propellant adaptive cohesive zone model, which specifically includes the following steps:

[0088] Step 1: Conduct a constant speed tensile test using a Type I propellant test piece to obtain a force-displacement curve of the Type I propellant test piece;

[0089] Step 2: Based on the area enclosed by the force-displacement curve of the Type I propellant specimen and the coordinate axis, as well as the thickness of the Type I propellant specimen and the maximum value of the crack extension displacement, calculate the cohesive energy reference value of the propellant adaptive cohesive zone model.

[0090] Step 3: Based on the cohesive strength reference value and the cohesive energy reference value of the propellant adaptive cohesive zone model, the propellant adaptive cohesive zone model is set as a linear reduction model, and the maximum separation displacement of the linear reduction model is calculated;

[0091] Based on the cohesive strength reference value and the cohesive energy reference value of the propellant adaptive cohesive zone model, the propellant adaptive cohesive zone model is set as a linear reduction model, and the maximum separation displacement of the linear reduction model is calculated, which specifically includes the following steps:

[0092] Step 1: The cohesive strength reference value of the propellant adaptive cohesive zone model is used as the vertical intercept of the linear reduction model, and the cohesive energy reference value of the propellant adaptive cohesive zone model is used as the area enclosed by the linear reduction model and the coordinate axis;

[0093] In this embodiment, the cohesive strength reference value of the propellant adaptive cohesive zone model is used as the vertical intercept of the linear reduction model, and the cohesive energy reference value of the propellant adaptive cohesive zone model is used as the area enclosed by the linear reduction model and the coordinate axis. The linear reduction model is drawn as follows: Figure 4 shown.

[0094] Step 2: Based on the vertical intercept of the linear reduction model and the area enclosed by it and the coordinate axis, calculate the horizontal intercept of the linear reduction model, that is, the maximum separation displacement of the linear reduction model.

[0095] In this embodiment, Figure 4 As shown, when the longitudinal intercept of the linear reduction model and the area enclosed by it and the coordinate axis are known, the transverse intercept of the linear reduction model, that is, the maximum separation displacement of the linear reduction model, is calculated. Figure 4 middle, represents the cohesive strength reference value of the propellant adaptive cohesive zone model, It represents the horizontal intercept of the linear reduction model, that is, the maximum separation displacement of the linear reduction model. represents the separation displacement, the ordinate Indicates cohesion.

[0096] Step 4: Based on the maximum separation displacement of the linear reduction model, set the control points on the linear reduction model;

[0097] In this embodiment, based on the maximum separation displacement of the linear reduction model, setting the control point on the linear reduction model specifically includes the following steps:

[0098] Step 1: Divide the maximum separation displacement of the linear reduction model into equal parts;

[0099] In this embodiment, the maximum separation displacement of the linear reduction model, that is, the cross-intercept of the linear reduction model is divided into equal parts.

[0100] Step 2: Set control points on the linear reduction model according to the horizontal coordinates corresponding to each equally divided point.

[0101] In this embodiment, control points are set on the linear reduction model according to the horizontal coordinates corresponding to the equally divided points of the linear reduction model's horizontal intercept, and the horizontal coordinate of each control point is the equally divided point of the linear reduction model's horizontal intercept.

[0102] Step 5: Based on the test results of the constant speed tensile test of the Type I propellant test piece, inversely calculate the cohesive force corresponding to each control point;

[0103] In this embodiment, based on the test results of the constant-speed tensile test of the Type I propellant test piece, the cohesive force corresponding to each control point is inversely calculated based on the force-displacement curve of the Type I propellant test piece and the horizontal coordinate of each control point using a finite element calculation model.

[0104] Step 6: Based on each control point and its corresponding cohesive force, obtain the propellant adaptive cohesive zone model.

[0105] In this embodiment, based on each control point and its corresponding cohesive force, obtaining the propellant adaptive cohesive zone model specifically includes the following steps:

[0106] Step 1: Based on the cohesion corresponding to each control point, the ordinate of each control point is updated to obtain a new control point;

[0107] In this embodiment, Figure 5 As shown, the horizontal coordinate of each control point is kept unchanged, and the vertical coordinate of each control point is updated based on the cohesion corresponding to each control point obtained by inversion calculation to obtain a new control point.

[0108] Step 2: Connect the new control points to form a propellant adaptive cohesive zone model.

[0109] In this embodiment, Figure 5 As shown, each new control point is connected to form a propellant adaptive cohesive zone model. Figure 5 middle, represents the cohesive strength reference value of the propellant adaptive cohesive zone model, It represents the horizontal intercept of the linear reduction model, that is, the maximum separation displacement of the linear reduction model. represents the separation displacement, the ordinate Indicates cohesion.

[0110] The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A method for determining a propellant adaptive cohesive zone model, characterized in that: include: A constant-speed tensile test was carried out using the first propellant test piece to obtain a reference value of the cohesive strength of the propellant adaptive cohesive zone model; A constant-speed tensile test was carried out using the second propellant test piece to obtain the cohesive energy reference value of the propellant adaptive cohesive zone model; Based on the cohesive strength reference value and the cohesive energy reference value of the propellant adaptive cohesive zone model, the propellant adaptive cohesive zone model is set as a linear reduction model, and the maximum separation displacement of the linear reduction model is calculated, including: taking the cohesive strength reference value of the propellant adaptive cohesive zone model as the vertical intercept of the linear reduction model, taking the cohesive energy reference value of the propellant adaptive cohesive zone model as the area enclosed by the linear reduction model and the coordinate axis; based on the vertical intercept of the linear reduction model and the area enclosed by the vertical intercept and the coordinate axis, calculating the horizontal intercept of the linear reduction model, that is, the maximum separation displacement of the linear reduction model; The control points are set on the linear reduction model based on the maximum separation displacement of the linear reduction model, including: dividing the maximum separation displacement of the linear reduction model into equal parts; and setting the control points on the linear reduction model according to the horizontal coordinates corresponding to the equal division points; Based on the test results of the constant speed tensile test of the second propellant test piece, the cohesive force corresponding to each control point is inversely calculated; Based on each control point and its corresponding cohesive force, a propellant adaptive cohesive zone model is obtained; The calculation formula of the cohesive strength reference value of the propellant adaptive cohesive zone model is: ； in, represents the cohesive strength reference value of the propellant adaptive cohesive zone model, represents the maximum value of the force in the force-displacement curve of the first propellant test piece, represents the cross-sectional area of ​​the first propellant test piece; The calculation formula of the cohesive energy reference value of the propellant adaptive cohesive zone model is: ； in, represents the cohesive energy reference value of the propellant adaptive cohesive zone model, represents the area enclosed by the force-displacement curve of the second propellant test piece and the coordinate axis, represents the thickness of the second propellant test piece, represents the maximum value of the crack extension displacement of the second propellant test piece, where represents the width of the second propellant test piece, Indicates the preset crack initiation length of the second propellant test piece.

2. The method for determining the propellant adaptive cohesive zone model according to claim 1, characterized in that: The first propellant test piece is a dumbbell-shaped propellant test piece; the second propellant test piece is a Type I propellant test piece.

3. The method for determining the propellant adaptive cohesive zone model according to claim 1, characterized in that: Based on the test results of the constant speed tensile test of the second propellant test piece, the cohesive force corresponding to each control point is calculated by inversion, including: Based on the force-displacement curve of the second propellant test piece, the cohesive force corresponding to each control point is inversely calculated using the finite element calculation model.

4. The method for determining the propellant adaptive cohesive zone model according to claim 1, characterized in that: Based on each control point and its corresponding cohesive force, the adaptive cohesive zone model of the propellant is obtained, including: Based on the cohesion corresponding to each control point, the ordinate of each control point is updated to obtain a new control point; The new control points are connected to form a propellant adaptive cohesive zone model.

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