Modeling of a special-shaped wire rope and load calculation method based on joint simulation of Adams and Abaqus

Abstract

The present invention provides a modeling method for special-shaped steel wire ropes and a load calculation method based on the joint simulation of Adams and Abaqus, and proposes a force analysis method based on the joint simulation of Adams dynamics and Abaqus finite element statics for triangular steel wire ropes. The method mainly includes the derivation of the mathematical geometric model of the triangular steel wire rope and the establishment of a three-dimensional geometric model, the dynamic simulation of Adams, the actual tensile test of the steel wire, the finite element pre-processing and statics simulation of Abaqus, and the development of an Abaqus pre-processing plug-in based on Python software. This method provides a relatively complete process specification and a reliable method reference for the modeling and load simulation analysis of special-shaped steel wire ropes, and provides a calculation method for in-depth exploration of the mechanical properties and damage failure mechanism of steel wire ropes and optimization of the structural design of steel wire ropes.

Description

Technical Field

[0001] The present invention belongs to the field of three-dimensional geometric modeling of steel wire ropes and load analysis and optimization of steel wire ropes, and relates to three-dimensional geometric modeling of special-shaped steel wire ropes and stress and strain analysis after loading. A method for solving the load of steel wire ropes under given working conditions is achieved by establishing an accurate three-dimensional geometric model of special-shaped steel wire ropes and combining Adams and Abaqus joint simulation. Background Art

[0002] Wire rope is an important mechanical equipment component with high strength and good flexibility. It mainly bears tensile and alternating loads. It has high tensile strength, fatigue resistance and impact toughness, and has a long load transmission distance. It is widely used in various industries. The characteristics of wire rope mainly depend on its special spatial spiral layered structure. According to the cross-sectional shape, wire rope can be divided into round strands and special-shaped strands, and special-shaped strands are further divided into triangular strands, elliptical strands and fan-shaped strands. Among them, the metal effective cross-sectional area of ​​triangular strands is large. When the diameter of the whole rope is the same and the strength of the steel wire is the same, the breaking tension of the triangular strand whole rope is about 25% higher than that of the round strand. Therefore, it is widely used in mining, lifting machinery and other fields. Although wire rope has the advantages of high tensile strength, good fatigue resistance and high impact toughness, wire rope is often accompanied by large load fluctuations during use. Excessive load will cause the wire rope to be damaged or broken prematurely, resulting in loss of personnel and property. In order to use wire rope safely and scientifically, it is necessary to study the load of the whole rope and the load of each steel wire constituting the whole rope under given working conditions. The research on the mechanical properties of wire rope can be divided into physical test and simulation analysis. The physical test is costly, and with the rapid development of numerical simulation technology, its simulation accuracy and solution efficiency have been greatly improved. Therefore, the numerical simulation method is used to study the loading condition of special-shaped wire rope.

[0003] Due to the complexity of the wire rope structure, most of the simulation research on wire ropes at home and abroad focuses on round strand wire ropes, and there is little research on special-shaped strand wire ropes. The document "Wang Xiaoyu. Parametric modeling and mechanical property analysis of wire ropes [D]. Jilin University, 2017." proposed a general parametric modeling method for typical wire ropes, and conducted finite element analysis on two types of failure forms of wire ropes. This document focuses on describing the parametric modeling method of typical wire ropes, but only applies a simple axial static load to the wire rope during the force analysis, which cannot reflect the actual force condition of the wire rope. The document "Chen Yuanpei. Research on the mechanics and friction and wear properties of wire rope strands [D]. Chongqing University, 2016." takes single-strand wire ropes as the object and studies the rope strand properties under axial load and bending load respectively in combination with its force condition. This document conducts theoretical analysis and finite element analysis on the mechanical properties of single-strand wire ropes, but only focuses on the single-strand model of round-strand wire ropes, which is too simplified compared with the wire rope model in practical applications. Therefore, a comprehensive and complete modeling and simulation analysis method needs to be proposed for special-shaped strand ropes in order to solve the loading conditions of the wire rope under given working conditions and ensure the safe, reliable and efficient use of the wire rope. Summary of the invention

[0004] The purpose of the present invention is to solve the problems of the difficulty in accurate three-dimensional geometric modeling of special-shaped strand steel wire ropes, imperfect force analysis process, oversimplification of load in finite element simulation, large difference from the actual force condition of the steel wire rope, and complicated finite element pre-processing process. A three-dimensional geometric modeling of special-shaped strand steel wire ropes and a steel wire rope force analysis method based on Adams and Abaqus joint simulation are proposed. The implementation process of the method is as follows Figure 1As shown. This method first establishes an accurate mathematical model of the entire rope by deriving the spatial structural geometric parameter equations of each steel wire in the triangular strand steel wire rope, and on this basis, generates a three-dimensional geometric model of the entire rope in combination with the cross-sectional shape of each steel wire; then, a dynamic model of the steel wire rope is created in the dynamic simulation software Adams, and the load condition of the steel wire rope under actual working conditions is solved through dynamic analysis. Subsequently, in order to obtain accurate material parameters (such as strength, elastic modulus, etc.), the actual tensile test of the steel wire is supplemented. Finally, the established three-dimensional geometric model of the steel wire rope is imported into Abaqus, and the force calculation results of the entire steel wire rope obtained by dynamic simulation and the material parameters obtained by the tensile test are input into Abaqus for finite element simulation. Due to the complexity of the geometric model of the steel wire rope and the presence of a large number of surfaces in the model, the pre-processing is cumbersome and time-consuming. Therefore, a solution software based on Abaqus was developed for the pre-processing and stress analysis of special-shaped stranded steel wire ropes. It can complete the cross-sectional property setting, meshing, constraint application and other operations of the steel wire rope in one click after inputting simple parameters, and use the dynamic simulation calculation results under real working conditions as input to apply loads to the steel wire rope and solve the analysis. This method provides a relatively complete process specification and a reliable method reference for the modeling and load simulation analysis of special-shaped stranded steel wire ropes, and provides a calculation method for in-depth exploration of the mechanical properties and damage failure mechanism of steel wire ropes and optimization of the structural design of steel wire ropes.

[0005] The object of the present invention is achieved in that the steps are as follows:

[0006] Step 1: Solve the parameter equations of the spatial spiral structure of each wire of the triangular strand wire rope and establish a three-dimensional geometric model of the entire rope;

[0007] Step 2: Conduct tensile test on the steel wires constituting the special-shaped steel wire rope to obtain the strength, yield limit and elastic modulus parameters of the steel wires;

[0008] Step 3: Perform wire rope dynamics simulation calculation in Adams;

[0009] Step 4: Import the calculation results of Adams into Abaqus for finite element simulation and stress-strain analysis.

[0010] The present invention also includes such structural features:

[0011] 1. The specific implementation method of step 1 is:

[0012] 1.1. During the twisting process of the wire rope, the distance that the side wire wire travels around the strand axis is called the strand twist moment p. The length of the wire rope in the straight rope state is l r , the spiral radius of the side strand core is r r , twist moment p and twist angle β r There are the following relationships between them:

[0013] tanβ r =p / (2πr r )

[0014] The steel wire maintains a circular cross section before and after twisting, and the spiral radius of the side strand in the rope is r r , the radius of the core strand is r core , the wire radius of the side strand is r i , where i is the number of steel wire layers of the side strand;

[0015] 1.2. Expand any side strand of the wire rope along the axis of the rope, and then expand the side wire of the side strand around the strand core. The length of the core strand, the expanded length of the side strand core, and the expanded length of the side strand side wire are expressed as l respectively. r , l s , l wi Indicates; θ r and θ si They represent the angles of twisting of the side strands around the core of the wire rope and the angles of twisting of the side strands around the core of the wire rope, β r , β si They represent the lay angle of the side strand core in the rope and the lay angle of the side strand wire in the strand respectively; r r and r si Indicates the spiral radius of the side strand core and the side strand side wire, and the spiral radius of each side wire r si The twist angle β of each side wire can be obtained by measuring the cross section of the wire rope. si Obtained by the following formula:

[0016]

[0017] Among them l s0 is the unfolded length of the strand core under a single twist moment, calculated by the following formula:

[0018]

[0019] After unfolding the single strand of triangular strand wire rope, the geometric relationship is as follows:

[0020] l r =r r θ r tanβ r ,

[0021] l s =r si θ si tanβ si ,

[0022] The angle θ of the twist of the side strands around the wire rope core r The angle θ of the side strands twisted around the strand core siThere are the following relationships:

[0023]

[0024] 1.3. Establish a global coordinate system O1-XYZ, fix the origin O1 on the rope core, the Z axis direction is the rope core axis direction, the XY plane is the wire rope cross section, the X axis points to the strand core, and the Y axis direction is determined according to the right-hand rule; establish a relative coordinate system on the center line of the side strand core - the dynamic Frenet frame O2-nbt, where O2 is an arbitrary point on the first-order space helix, t is the unit tangent vector of any point on the center line of the helix, n is the unit principal normal vector, and b is the unit binormal vector. If a point A on the first-order space helix is ​​represented by vector R in the global coordinate system, a point B on the second-order space helix is ​​represented by vector Q in the Frenet coordinate system, and the vector formed by the line connecting point B and the origin O1 of the global coordinate system is represented by P; the vector expression of the second-order space helix P = Q + R is obtained;

[0025] After the strand core wire is twisted once, the expression of the strand core wire in the global coordinate system can be obtained. Assume that the parametric equation R of the side strand core wire is:

[0026]

[0027] Find the first and second derivatives of R respectively:

[0028]

[0029]

[0030] Obtain the Frenet frame coordinates on the first-order spiral:

[0031]

[0032]

[0033]

[0034] The Frenet frame coordinate system can be represented by the matrix T:

[0035]

[0036] The transformation relationship between the Frenet local coordinate system and the global coordinate system is:

[0037]

[0038] Suppose the coordinates of a point on the quadratic helix in this coordinate frame are [r si cosθ s , r si sinθs ,0] T , the expression of the quadratic helix in global coordinates is:

[0039]

[0040] In the above formula, r r is the spiral radius of the centroid of the side strand, r si is the spiral radius of the side strand side silk centerline, θ r is the rotation angle of the side strand core mass center line, θ si is the rotation angle of the side strand’s side silk centerline, β r is the helix angle of the centroid of the side strand; the initial positions of the inner and outer steel wires of each strand in the Frenet frame have a certain distribution law, and the expression of the side strand wire in the global coordinate system is:

[0041]

[0042] The initial position of each side wire can be measured according to the cross section of the entire wire rope; the coefficient n is introduced to limit the rotation direction of the wire during spiral twisting, and the parametric equation of the side strand and side wire in the global coordinate system is rewritten; let but θ r Use θ si and n, the parametric equation of the lateral strand in the global coordinate system is expressed as:

[0043]

[0044] 1.4. Based on the derived mathematical model of the wire rope centroid, a three-dimensional geometric model of the triangular strand wire rope is established.

[0045] 2. Step 3 specifically includes:

[0046] 3.1 Create a small ball in Adams, set its density, elastic modulus and Poisson's ratio to simulate the heavy objects lifted in the mine in actual working conditions;

[0047] 3.2 Using Adams' Cable module, the continuous steel wire rope is discretized into multiple rigid bodies. Each rigid body is connected by constraints or sleeve forces to simulate the flexibility of the steel wire rope. The contact force is defined between each rigid body and the pulley to simulate the movement of the steel wire rope around the pulley. The starting and ending points of the rope are established. The material parameters obtained by the steel wire tensile test are used to set the density, elastic modulus and Poisson's ratio of the rope in the rope parameter options. The discrete body units of the steel wire rope are connected by the flexible connection method of Bushing linear sleeve force.

[0048] 3.3 Create a pulley that matches the rope according to the structure of the mine wire rope hoisting device, simulate the loading process of the wire rope through the pulley, mass block and sliding spoke, and set the contact force between the pulley and the wire rope, the material properties of the mass block, and the speed and acceleration parameters respectively;

[0049] 3.4 is the speed applied to the lifting end of the wire rope, simulating the heavy object lifting process, obtaining the load data of the calibrated points on the wire rope, and obtaining the calculation results.

[0050] 3. Step 4 specifically includes:

[0051] 4.1 Import the 3D solid model of the triangular strand steel wire rope, set the material parameters and assign cross-sectional properties to each steel wire according to the results of the actual tensile test of the steel wire, and generate an assembly;

[0052] 4.2 Create an analysis step, set the starting step size, minimum step size and maximum incremental step size of the analysis step;

[0053] 4.3 Set contact pairs for adjacent steel wires in the triangular strand steel wire rope, and use the contact pairs to make contact between each steel wire and its adjacent steel wire;

[0054] 4.4 Grid division: according to the characteristics of the unit and the applicable principles, use hexahedral units to divide the grid, and select the "neutral axis algorithm" for the algorithm of the grid control properties;

[0055] 4.5 Divide the end face of the wire rope model into a free end and a fixed end, and set coupling constraints for the wire rope end face for the free end and the fixed end respectively;

[0056] 4.6 Set boundary conditions and use Adams calibration point loading data as load input, and submit for calculation and analysis.

[0057] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention designs a force analysis method for triangular strand steel wire ropes based on the joint simulation of Adams and Abaqus, and simulates the load conditions of triangular strand steel wire ropes under actual working conditions through Adams dynamic simulation, which makes up for the shortcomings of the existing test methods in that the load application part is too simple and the load data lacks support from actual working conditions. The triangular strand steel wire rope was subjected to a tensile test to obtain the actual values ​​of the material parameters of steel wires of different diameters of the triangular strand steel wire rope, thus avoiding the errors caused by the use of theoretical values ​​of the material parameters. At the same time, an accurate three-dimensional geometric model was established, and the internal force conditions of the triangular strand steel wire rope were obtained through finite element simulation analysis in Abaqus. On this basis, an Abaqus finite element pre-processing plug-in for a specific model of triangular strand steel wire rope was developed using the Python language, which greatly improved the pre-processing efficiency of the model, and the plug-in interface is concise and intuitive, and the operation is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a specific flow chart of the present invention.

[0059] Figure 2 It is the geometric structure diagram of the steel wire rope of the present invention.

[0060] Figure 3 It is an expanded view of the side wire of the steel wire rope of the present invention.

[0061] Figure 4 It is a spatial spiral curve diagram under the Frenet global coordinate system and the local coordinate system of the present invention.

[0062] Figure 5 This is a schematic diagram of the dynamic model structure of the mine wire rope hoisting mechanism.

[0063] Figure 6 The figure shows the geometric structure of a triangular strand steel wire rope and the distribution diagram of each layer of steel wires according to an embodiment of the present invention.

[0064] Figure 7 This is a diagram showing the numbering of the side strands and side wires of a triangular strand steel wire rope according to an embodiment of the present invention.

[0065] Figure 8 The figure is a single-strand spatial spiral curve diagram of a triangular-strand steel wire rope based on MATLAB according to an embodiment of the present invention.

[0066] Fig. 9 The figure is a three-dimensional geometric model diagram of a triangular strand steel wire rope based on UG according to an embodiment of the present invention.

[0067] Fig.10 The figure is a scene diagram of a steel wire tensile test according to an embodiment of the present invention.

[0068] Fig.11 The present invention is a dynamic model of a mine wire rope hoisting mechanism based on Adams according to an embodiment of the present invention.

[0069] Fig.12 The figure is a dynamic simulation result of a mine wire rope hoisting mechanism under a specific working condition based on Adams according to an embodiment of the present invention.

[0070] Fig.13 The figure is a finite element statics simulation result of a triangular strand steel wire rope based on Abaqus according to an embodiment of the present invention.

[0071] Fig.14 This is a diagram of the interface of an Abaqus-based pre-processing plug-in according to an embodiment of the present invention. DETAILED DESCRIPTION

[0072] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0073] The present invention comprises the following steps:

[0074] Step 1: Solve the parametric equations of the spatial helical structure of each wire of the triangular strand wire rope and establish a three-dimensional geometric model of the entire rope.

[0075] The specific implementation method of the above step 1 is:

[0076] 1.1 During the twisting process of the wire rope, the distance that the side wire wire travels around the strand axis is called the strand twist moment p, that is, the shortest longitudinal distance of the same wire on the strand. The length of the wire rope in the straight rope state is l r , the spiral radius of the side strand core is r r ,like Figure 2 shown.

[0077] Then the twist moment p and twist angle β r There are the following relationships between them:

[0078] tanβ r =p / (2πr r )

[0079] Assuming that the steel wire maintains a circular cross-section before and after twisting, the spiral radius of the side strand in the rope is r r , the radius of the core strand is r core , the wire radius of the side strand is r i , where i is the number of steel wire layers in the side strand.

[0080] 1.2 Expand any side strand of the wire rope along the axis of the rope, and then expand the side wire of the side strand around the strand core to obtain the following: Figure 3 The geometric relationship of the wire rope is shown in the figure. The length of the core strand (i.e. the length of the wire rope), the unfolded length of the side strand core, and the unfolded length of the side strand side wire are represented by l r , l s , l wi Indicates; θ r and θ si Respectively represent the angle of twist of the side strands around the core of the wire rope and the angle of twist of the side strands around the core. r , β si They represent the lay angle of the side strand core in the rope and the lay angle of the side strand wire in the strand respectively; r r and r si It indicates the spiral radius of the side strand core and the side strand side wire, and can also be called the twisting radius.

[0081] The spiral radius r of each side wire si The twist angle β of each side wire can be obtained by measuring the cross section of the wire rope. si Obtained by the following formula:

[0082]

[0083] Among them l s0 is the unfolded length of the strand core under a single twist moment, which can be calculated by the following formula:

[0084]

[0085] The twist angle and spiral radius of the inner and outer layers of the triangular strands are different. The spiral radius and twist angle of each layer of wire need to be determined according to the wire rope design specifications. After the single strand of the triangular strand wire rope is unfolded, the geometric relationship is as follows:

[0086] l r =r r θ r tanβ r ,

[0087] l s =r si θ si tanβ si ,

[0088] Therefore, the angle θ at which the side strands are twisted around the wire rope core strands r The angle θ of the side strands twisted around the strand core si There are the following relationships:

[0089]

[0090] 1.3 In order to obtain the spatial geometric parameter equations of each steel wire in the wire rope, it is necessary to derive the centroid line parameter equations of the side strand core and side wire, that is, the linear and quadratic space helix equations. Establish a global coordinate system O1-XYZ, fix the origin O1 on the rope core, the Z-axis direction is the rope core axis direction, the XY plane is the wire rope cross section, the X-axis points to the strand core, and the Y-axis direction is determined according to the right-hand rule. The centerline equation of the side wire is a quadratic space spiral curve, so a relative coordinate system on the centerline of the side strand core is established - the dynamic Frenet frame O2-nbt, where O2 is an arbitrary point on the linear space helix, t is the unit tangent vector of any point on the centerline of the helix, n is the unit principal normal vector, and b is the unit binormal vector, such as Figure 4 shown.

[0091] If a point A on the primary spiral is represented by vector R in the global coordinate system, a point B on the secondary spatial spiral is represented by vector Q in the Frenet coordinate system, and the vector formed by the line connecting point B and the origin O1 of the global coordinate system is represented by P. From this, the vector expression of the secondary spatial spiral can be deduced as P=Q+R.

[0092] After the strand core wire is twisted once, the expression of the strand core wire in the global coordinate system can be obtained. Assume that the parameter equation R of the side strand core wire (primary helix) is:

[0093]

[0094] Find the first and second derivatives of R respectively:

[0095]

[0096]

[0097] Obtain the Frenet frame coordinates on the first-order spiral:

[0098]

[0099]

[0100]

[0101] The Frenet frame coordinate system can be represented by the matrix T:

[0102]

[0103] The transformation relationship between the Frenet local coordinate system and the global coordinate system is:

[0104]

[0105] Suppose the coordinates of a point on the quadratic helix in this coordinate frame are [r si cosθ s , r si sinθ s ,0] T , the expression of the quadratic helix in global coordinates is

[0106]

[0107] In the above formula, r r is the spiral radius of the centroid of the side strand, r si is the spiral radius of the side strand side silk centerline, θ r is the rotation angle (twisting angle) of the center of mass of the side strands, θ si is the rotation angle (twisting angle) of the side strand’s side silk centerline, β r is the helix angle of the centroid of the side strand.

[0108] The initial positions of the inner and outer steel wires of each strand in the Frenet frame have a certain distribution pattern, so the expression of the side strand and side wire in the global coordinate system is:

[0109]

[0110] The initial position of each side wire can be measured based on the cross-section of the entire wire rope.

[0111] The starting point of the steel wire centroid has an important influence on the uniformity of steel wire distribution. For special-shaped strand steel wire ropes, in order to make the steel wires evenly distributed in the twisting layer, the distance between the centroids of adjacent steel wires in the axial direction should be equal during the twisting process. Therefore, the coefficient n is introduced to limit the rotation direction of the steel wire during spiral twisting, and rewrite the parametric equations of the side strands and side wires in the global coordinate system.

[0112] make but θ r Use θ si and n, the parametric equation of the side strand and side wire in the global coordinate system can be expressed as:

[0113]

[0114] At this point, the mathematical derivation of the geometric model of triangular strand wire rope has been completed.

[0115] 1.4 Based on the mathematical model of the wire rope centroid derived in 1.1, program and solve the coordinates of the centroid of each wire that constitutes the special-shaped wire rope in MATLAB, and export the coordinate data of the points on the centroid of each wire in dat format.

[0116] Import the coordinate point data dat file on the steel wire mass center line into UG, and use the spline function to generate the mass center line of each steel wire. Then create a sketch plane at the end point of each mass center line, draw the cross-sectional shape of each steel wire, and generate the solid model of the wire rope by sweeping.

[0117] At this point, the three-dimensional geometric model of the triangular strand wire rope has been established.

[0118] Step 2: Conduct tensile test on the steel wires constituting the special-shaped steel wire rope to obtain the strength, yield limit, elastic modulus and other parameters of the steel wires.

[0119] First, the entire rope wire is separated and straightened. Since the wire rope is oiled or soaked in oil before leaving the factory, it is necessary to soak the wire rope in alcohol to clean the oil stains on the surface of the wire rope after it is removed. After cleaning, use a wire rope straightening machine to straighten the wire. Compared with manual straightening, the straightening machine will not damage the metallographic structure of the wire. After straightening, the wire rope has better straightness and high work efficiency.

[0120] Next, the steel wire was cut into 15cm long specimens, 10 specimens of each diameter, and the specimen was placed on the testing machine head and the extensometer was installed. After installation, the equipment was reset and the test rate was controlled by the strain rate. The relevant indicators refer to GB / T228.1-2010 "Methods for Tensile Test of Metallic Materials".

[0121] Finally, take the samples that have successfully completed the experiment (no slippage during the test and the fracture position of the sample is within the gauge length), obtain the ultimate strength and yield limit, draw the stress-strain curve, and calculate the elastic modulus and Poisson's ratio of the steel wire according to GB / T22315-2008.

[0122] The elastic modulus E is calculated by the following formula:

[0123]

[0124] ΔF is the change in the axial force of the specimen, S0 is the cross-sectional area of ​​the specimen, Δ l is the axial deformation variation of the specimen, L el is the axial extensometer gauge length.

[0125] Poisson's ratio μ is calculated by the following formula:

[0126]

[0127] where Δ t is the lateral deformation variation, L et is the lateral deformation of the specimen.

[0128] So far, the material properties of the steel wires constituting the special-shaped strand steel wire rope have been obtained through the steel wire rope tensile test.

[0129] Step 3: Perform wire rope dynamics simulation calculation in Adams.

[0130] The specific implementation method of the above step 3 is:

[0131] 3.1 Create a small ball in Adams, set its density, elastic modulus and Poisson's ratio to simulate the heavy objects lifted in the mine in actual working conditions.

[0132] 3.2 Using the Cable module provided by Adams, the continuous wire rope is discretized into multiple rigid bodies. Each rigid body is connected by constraints or sleeve forces to simulate the flexibility of the wire rope. The contact force is defined between each rigid body and the pulley to simulate the movement of the wire rope around the pulley. When the length of each rigid body is small enough relative to the entire wire rope, the mechanical properties of the wire rope can be reflected more accurately. The discrete body model retains the mass, inertia, and tensile, bending, and torsional stiffness of the rope based on the beam formula. Its advantage is that it has a high degree of fit with the actual situation, can better simulate the force conditions of the wire rope, and can realize the winding action between the wire rope and the pulley.

[0133] Establish the starting and ending points of the rope, obtain the material parameters through the wire tensile test, set the density, elastic modulus and Poisson's ratio of the rope in the rope parameter options, and connect the discrete body units of the wire rope using the flexible connection method of Bushing linear sleeve force.

[0134] 3.3 According to the structure of the mine wire rope hoisting device, create a pulley that matches the rope, and use the pulley, mass block and sliding spoke in Adams to simulate the loading process of the wire rope. Set the contact force between the pulley and the wire rope, the material properties of the mass block, the speed and acceleration parameters, etc. Figure 5 shown.

[0135] 3.4 is the speed applied to the lifting end of the wire rope, simulating the heavy object lifting process, obtaining the load data of the calibrated points on the wire rope, and obtaining the calculation results.

[0136] Step 4: Import the calculation results of Adams into Abaqus for finite element simulation.

[0137] The specific implementation method of step 4 above is:

[0138] 4.1 Import the three-dimensional solid model of the triangular strand steel wire rope, set the material parameters (density, elastic modulus and Poisson's ratio) according to the results of the actual tensile test of the steel wire, assign cross-sectional properties to each steel wire, the cross-sectional type is Solid, the cross-sectional properties are homogeneous, and generate an assembly.

[0139] 4.2 Create an analysis step, set the starting step size, minimum step size and maximum incremental step size of the analysis step. The step size setting of the analysis step needs to be adjusted according to the complexity of the model, the type of load, the contact situation and the mesh density to achieve the purpose of calculation convergence. Since the force analysis of the key parts of the wire rope involves large deformation of the model, in order to speed up the calculation convergence, it is necessary to set the automatic stability calculation method and turn on the geometric nonlinearity.

[0140] 4.3 Contact pairs are set for adjacent steel wires in the triangular strand steel wire rope. Due to the complex internal contact situation of the steel wire rope, it is difficult to converge the calculation using general contact. Therefore, contact pairs (surface-to-surface contact) are used to impose contact between each steel wire and its adjacent steel wire.

[0141] The default contact behavior in Abaqus / Standard is hard contact ("Hard" Contact). The contact surface constraint application algorithm of hard contact selects a penalty function of penalty stiffness (Penalty). The penalty function friction allows the contact surface to have "elastic slip", which is suitable for most contact problems.

[0142] To create the interaction between the surfaces of the wire ropes, first create the interaction properties and select "Contact"; in the contact property options, add "Tangential Behavior" and "Normal Behavior", the friction formula for the tangential behavior is penalty friction, and the friction coefficient is set to 0.15 based on the friction coefficient between steel and steel; set the normal behavior to "Hard Contact", and use the default values ​​for the rest.

[0143] 4.4 Grid division: According to the characteristics of the unit and the applicable principles, hexahedral units are used to divide the grid, and the algorithm of the grid control attribute is selected as the "neutral axis algorithm". Since the overall seeding generates the same density grid in the axial and radial directions, the overall seeding of the steel wire with a large aspect ratio will lead to two situations: the axial grid is too sparse and difficult to converge during calculation, or the radial grid is too dense, increasing the calculation cost. Therefore, it is necessary to add busbars to the steel wire, and seed the busbars and cross-sections of the steel wire by edge to achieve the purpose of rapid convergence during calculation and improve the calculation speed.

[0144] 4.5 According to the load conditions, the end faces of the wire rope model can be divided into free ends and fixed ends. Coupling constraints (Coupling) of the wire rope end faces are set for the free ends and fixed ends respectively. First, create a reference point at the center of the wire rope, then add a coupling constraint, select the reference point as the control point, set the constraint type to "surface", and select all end faces in the view. The fixed end needs to constrain the end face with six degrees of freedom, while the free end needs to constrain the axial rotational degree of freedom, otherwise the wire rope will be straightened and spread out during the force process, which does not meet the force characteristics of the wire rope after twisting.

[0145] 4.6 Set boundary conditions and use Adams calibration point loading data as load input, and submit for calculation and analysis.

[0146] This method proposes a force analysis method for triangular strand steel wire rope based on joint simulation of Adams dynamics and Abaqus finite element statics. This method mainly includes the derivation of the mathematical geometric model of triangular strand steel wire rope and the establishment of a three-dimensional geometric model, Adams dynamics simulation, steel wire physical tensile test, Abaqus finite element pre-processing and statics simulation, and the development of Abaqus pre-processing plug-in based on Python software.

[0147] Example 1

[0148] Taking the model 6V×34-FC, right-handed straight-twist triangular strand wire rope as an example, the specific steps include:

[0149] Step 1: Establish a mathematical model of a triangular strand wire rope. The wire rope has a diameter of 30 mm and has 34 wires in the side strand, which are divided into inner wire, middle wire and outer wire. The radii of the center wire, inner wire and outer wire of the side strand are r1, r2 and r3 respectively. Figure 6 According to the parametric equation of the spatial spiral structure of each wire of the triangular strand wire rope, the parametric equation of the centroid of the side strand core is:

[0150]

[0151] The parametric equation of the side strand and side silk centroid is:

[0152]

[0153] The twist angle and helical radius of the inner and outer wires of the triangular strand are also different. The helical radius and twist angle of each layer of wire need to be determined according to the wire rope design specifications. There are 8 types of helical radius and twist angle for the side wires in the strand, that is, i = 8, such as Figure 7 The spiral radius and twist angle parameters of each side wire are shown in Table 1-1.

[0154] Table 1-1 Spiral radius and twist angle of each side wire

[0155]

[0156] The initial position of each side wire can be measured based on the sketch of the wire rope cross section, as shown in Table 1-2.

[0157] Table 1-2 Initial positions of each side wire

[0158]

[0159]

[0160] The correspondence between program symbols in MATLAB programming and mathematical expression symbols in 1.1.1 is shown in Table 1-3.

[0161] Table 1-3 Parameter symbol comparison table

[0162]

[0163]

[0164] Generate 34 steel wires of a single strand of wire rope through MATLAB and draw an image of the steel wire centroid line, as shown in Figure 8 The discrete interval of the twist angle of the core strand and the side wire is 0.005, each steel wire is discretized into 5440 points, and the coordinates of the discrete points are exported in dat format.

[0165] Use UG's spline function to generate the centroid of each steel wire. Select "Through Point" in the spline curve tab, continue to select "Point in File", select the steel wire coordinate file to be generated, select the curve type as multi-segment, and select the default 3 times for curve fitting. Create a reference plane at the endpoint of each center line. The reference plane is required to be perpendicular to the tangent of the curve at the endpoint. Create a sketch on the created reference plane. Take the center line endpoint as the origin, and make the cross-section circle of each steel wire. Generate a solid model of the wire rope by sweeping, such as Fig. 9 shown.

[0166] Step 2: Carry out the actual tensile test of the steel wire. First, disassemble the triangular steel wire rope, use a straightening machine to straighten the disassembled steel wire, cut 10 steel wires of different diameters from the single-strand rope, cut them into 15cm long specimens, add the specimen to the testing machine head, and install the extensometer.

[0167] After installation, the equipment is reset, and the test rate is controlled by strain rate. The relevant indicators refer to GB / T228.1-2010 "Methods for tensile test of metal materials" to carry out tensile test of steel wire, such as Fig.10 shown.

[0168] Finally, the successful samples were taken (no slippage during the test and the fracture position of the sample was within the gauge length), the ultimate strength and yield limit were obtained, the stress-strain curve was drawn, and the elastic modulus and Poisson's ratio of the steel wire were calculated according to GB / T22315-2008, and the density of the triangular strand steel wire rope was obtained to be 7.784e -9 kg / mm 3 The elastic modulus of the inner steel wire with a diameter of 1.15 mm is 2.098e 5 MPa, Poisson's ratio is 0.319, and the elastic modulus of the middle steel wire with a diameter of 1.6 mm is 2.103e 5 MPa, Poisson's ratio is 0.32, and the elastic modulus of the outer steel wire with a diameter of 2.6 mm is 2.113e 5MPa, and Poisson's ratio is 0.318.

[0169] Step 3: Use the rope module provided by Adams to create a dynamic model of the mine wire rope hoisting mechanism. Since the rope module simplifies the complex internal structure of the wire rope, the material parameters in step 2 are taken as the material parameters of the wire rope dynamic model. Set the density of the wire rope to 7.784e -9 kg / mm 3 , elastic modulus is 2.100e 5 MPa, Poisson's ratio is 0.319. Three pulleys, two mass blocks and two sliding spokes are used to simulate the structure of the mine wire rope hoisting mechanism. The pulleys on the left and right sides are fixed pulleys, and the distance between the fixed pulleys is 3m. The pulley between the static pulleys is the movable pulley, and the cargo is simplified as a sphere, which is connected to the movable pulley through a rotating pair. Both sides of the rope are connected to the frictional mass blocks, and sliding pairs are set at the center of mass of the two mass blocks. The Adams dynamic model of the mine wire rope hoisting mechanism is as follows: Fig.11 shown.

[0170] Apply a lifting speed of 0.05m / s to the mass block on the right. Through dynamic simulation, the load condition of the wire rope in the mine wire rope lifting mechanism is obtained. The load curve of the wire rope at the calibration point is as follows: Fig.12 As shown, the load curve shows that the mine wire rope lifting mechanism reaches a balanced state at about 0.4s, that is, the weight is in a uniform rising state. At this time, the load size at the wire rope calibration point is 4250N, and the load size remains unchanged thereafter.

[0171] Step 4: Import the 3D geometric model of the triangular strand steel wire rope, and set the density, elastic modulus, and Poisson's ratio obtained in step 2 for the three types of steel wires according to the results of the actual tensile test of the steel wires. Create a solid homogeneous section, and assign section properties to each steel wire to generate an assembly.

[0172] Create a static analysis step, turn on the large deformation switch, set the automatic stabilization algorithm, and set the starting step length of the analysis step to 10 -7 , the minimum step size is set to 10 -9 , the maximum increment step is 1000.

[0173] Contact pairs are set for adjacent steel wires in the triangular strand wire rope. Reference points RP1 and RP2 are created at the free end and fixed end of the wire rope respectively. Constraints are added with reference points as constraint points and all wire end faces in the wire rope as objects. At the same time, boundary conditions are set to constrain all six degrees of freedom at the fixed end and only constrain the axial rotational degree of freedom at the free end to prevent the wires in the strand from spreading out when the wire rope is loaded.

[0174] The steel wires are seeded by edge, and the busbars of the steel wires are added. The number of seeds for the busbars is 200, and the number of seeds for the end faces is 16. The central axis algorithm is selected to generate the mesh of the triangular strand steel wire rope.

[0175] The load data of Adams' calibration points are used as load input, and a concentrated force load is applied to the free end reference point RP2 of the wire rope, with the direction perpendicular to the free end face, and then submitted for calculation and analysis. The finite element static analysis results of the triangular strand wire rope show that under the load calculated by Adams dynamic simulation, the maximum stress of the triangular strand wire rope appears on the outermost wires of each side strand, and is symmetrically distributed, concentrated at the position farthest from the rope core and close to the end face. The distribution trend of the free end and the fixed end is the same, and the maximum stress value is 21.84MPa. Fig.13 shown.

[0176] The pre-processing stage includes setting material parameters, assigning section properties, creating analysis steps, designing value contact pairs, adding constraints, setting boundary conditions, dividing meshes, and inputting loads through the Abaqus plug-in. The plug-in uses Python scripts to achieve one-click setting of pre-processing parameters. The specific code is as follows:

[0177]

[0178]

[0179] The plugin interface is as follows Fig.14 shown.

Claims

1. A modeling method for special-shaped steel wire rope and a load calculation method based on Adams and Abaqus joint simulation, characterized in that: Here are the steps: Step 1: Solve the parameter equations of the spatial spiral structure of each wire of the triangular strand wire rope and establish a three-dimensional geometric model of the entire rope; Step 2: Conduct tensile test on the steel wires constituting the special-shaped steel wire rope to obtain the strength, yield limit and elastic modulus parameters of the steel wires; Step 3: Perform wire rope dynamics simulation calculation in Adams; Step 3.1: Create a small ball in Adams, set its density, elastic modulus and Poisson's ratio to simulate the heavy objects lifted in the mine in actual working conditions; Step 3.2: Use the Cable module of Adams to discretize the continuous wire rope into multiple rigid bodies. Each rigid body is connected by constraints or sleeve forces to simulate the flexibility of the wire rope. The contact force is defined between each rigid body and the pulley to simulate the movement of the wire rope around the pulley. The starting and ending points of the rope are established. The density, elastic modulus and Poisson's ratio of the rope are set in the rope parameter options based on the material parameters obtained by the wire tensile test. The discrete body units of the wire rope are connected using the flexible connection method of Bushing linear sleeve force. Step 3.3: Create a pulley that matches the rope according to the structure of the mine wire rope hoisting device, simulate the loading process of the wire rope through the pulley, mass block and sliding spoke, and set the contact force between the pulley and the wire rope, the material properties of the mass block, and the velocity and acceleration parameters respectively; Step 3.4: Apply velocity to the lifting end of the wire rope to simulate the lifting process of heavy objects, obtain the load data of the calibrated points on the wire rope, and obtain the calculation results; Step 4: Import the calculation results of Adams into Abaqus for finite element simulation and stress-strain analysis; Step 4.1: Import the 3D solid model of the triangular strand steel wire rope, set the material parameters and assign cross-sectional properties to each steel wire according to the results of the actual tensile test of the steel wire, and generate an assembly; Step 4.2: Create an analysis step and set the starting step size, minimum step size, and maximum incremental step size of the analysis step; Step 4.3: Set contact pairs for adjacent steel wires in the triangular strand steel wire rope, and use the contact pairs to apply contact between each steel wire and its adjacent steel wire; Step 4.4: Divide the mesh. According to the characteristics of the unit and the applicable principles, use hexahedral units to divide the mesh. Select the "neutral axis algorithm" for the algorithm of the mesh control properties. Step 4.5: Divide the end face of the wire rope model into a free end and a fixed end, and set coupling constraints for the wire rope end face for the free end and the fixed end respectively; Step 4.6: Set boundary conditions and use Adams calibration point loading data as load input, and submit for calculation analysis.

2. The modeling of a special-shaped strand steel wire rope and the load calculation method based on Adams and Abaqus joint simulation according to claim 1 are characterized in that: The specific implementation method of step 1 is: 1.

1. During the twisting process of the wire rope, the distance that the side wire wire travels around the strand axis is called the strand twist moment p. The length of the wire rope in the straight rope state is l r , the spiral radius of the side strand core is r r , twist moment p and twist angle β r There are the following relationships between them: tanβ r =p / (2πr r ) The steel wire maintains a circular cross section before and after twisting, and the spiral radius of the side strand in the rope is r r , the radius of the core strand is r core , the wire radius of the side strand is r i , where i is the number of steel wire layers of the side strand; 1.

2. Expand any side strand of the wire rope along the axis of the rope, and then expand the side wire of the side strand around the strand core. The length of the core strand, the expanded length of the side strand core, and the expanded length of the side strand side wire are expressed as l respectively. r , l s , l wi Indicates; θ r and θ si They represent the angles of twisting of the side strands around the core of the wire rope and the angles of twisting of the side strands around the core of the wire rope, β r , β si They represent the lay angle of the side strand core in the rope and the lay angle of the side strand wire in the strand respectively; r r and r si Indicates the spiral radius of the side strand core and the side strand side wire, and the spiral radius of each side wire r si The twist angle β of each side wire can be obtained by measuring the cross section of the wire rope. si Obtained by the following formula: Among them l s0 is the unfolded length of the strand core under a single twist moment, calculated by the following formula: After unfolding the single strand of triangular strand wire rope, the geometric relationship is as follows: l r =r r i r tanβ r , l s =r si i si tanβ si , The angle θ of the twist of the side strands around the wire rope core r The angle θ of the side strands twisted around the strand core si There are the following relationships: 1.

3. Establish a global coordinate system O1-XYZ, fix the origin O1 on the rope core, the Z axis direction is the rope core axis direction, the XY plane is the wire rope cross section, the X axis points to the strand core, and the Y axis direction is determined according to the right-hand rule; establish a relative coordinate system on the center line of the side strand core - the dynamic Frenet frame O2-nbt, where O2 is an arbitrary point on the first-order space helix, t is the unit tangent vector of any point on the center line of the helix, n is the unit principal normal vector, and b is the unit binormal vector. If a point A on the first-order space helix is ​​represented by vector R in the global coordinate system, a point B on the second-order space helix is ​​represented by vector Q in the Frenet coordinate system, and the vector formed by the line connecting point B and the origin O1 of the global coordinate system is represented by P; the vector expression of the second-order space helix P = Q + R is obtained; After the strand core steel wire is twisted once, the expression of the strand core steel wire in the global coordinate system can be obtained; the parameter equation R of the side strand core steel wire is: Find the first and second derivatives of R respectively: Obtain the Frenet frame coordinates on the primary spiral: The Frenet frame coordinate system can be represented by the matrix T: The transformation relationship between the Frenet local coordinate system and the global coordinate system is: Suppose the coordinates of a point on the quadratic helix in this coordinate frame are [r si cosθ s , r si sinθ s ,0] T , the expression of the quadratic helix in global coordinates is: In the above formula, r r is the spiral radius of the centroid of the side strand, r si is the spiral radius of the side strand side silk centerline, θ r is the rotation angle of the side strand core mass center line, θ si is the rotation angle of the side strand’s side silk centerline, β r is the helix angle of the centroid of the side strand; the initial positions of the inner and outer steel wires of each strand in the Frenet frame have a certain distribution law, and the expression of the side strand wire in the global coordinate system is: The initial position of each side wire can be measured according to the cross section of the entire wire rope; the coefficient n is introduced to limit the rotation direction of the wire during spiral twisting, and the parametric equation of the side strand and side wire in the global coordinate system is rewritten; let but θ r Use θ si and n, the parametric equation of the lateral strand in the global coordinate system is expressed as: 1.

4. Based on the derived mathematical model of the wire rope centroid, a three-dimensional geometric model of the triangular strand wire rope is established.

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