WO2015072040A1

WO2015072040A1 - Resin flow behavior calculation method, and resin flow behavior calculation program

Info

Publication number: WO2015072040A1
Application number: PCT/JP2013/081074
Authority: WO
Inventors: 河野　務; 宇亨池田; 孝仁村木
Original assignee: 株式会社日立製作所
Priority date: 2013-11-18
Filing date: 2013-11-18
Publication date: 2015-05-21

Abstract

In a resin flow behavior calculation method for predicting the elastic coefficient distribution of a resin material formed by coming into contact with a gaseous body: a shape model of a space filled with the resin material is inputted and is broken down into three-dimensional solid elements on the basis of the space model data; the physical property values of the resin material such as the density, thermal conductivity and specific heat thereof, and boundary conditions at least containing the initial temperature of the resin material, and the heat-transfer coefficient of the resin and the gaseous body are inputted; the elastic coefficient of the resin is inputted as an equation including the changes in the resin temperature; and an equation of continuity, Navier-Stokes equations, and an energy conservation equation are computed on the basis of the three-dimensional solid elements. As a consequence, the distribution of the inputted elastic coefficient of the resin is calculated when calculating the resin temperature, speed and pressure for each time step.

Description

Calculation method of resin flow behavior and calculation program of resin flow behavior

The present invention, for example, for determining the molding process conditions for increasing the adhesion of the coating resin to the core wire in the manufacturing process of the wire material in which the core wire and the molten resin are extruded from the cylinder and the core wire is coated with the resin. The present invention relates to a resin flow behavior calculation method and a resin flow behavior calculation program.

In the manufacturing process of the resin-coated wire, the resin material that covers the core wire is extruded from the cylinder, cooled in the air, and cured so as to cover the periphery of the core wire without gaps, and formed as a coated wire. In order to optimally design the molding process conditions, a method for calculating the flow behavior of the resin material is necessary in consideration of heat transfer between the resin and the gas when the resin material is molded in contact with the gas.

Patent documents relating to the calculation method of the flow behavior of the resin material include, for example, Patent Document 1 “Japanese Patent Laid-Open No. 2006-205740” and Patent Document 2 “Japanese Patent Laid-Open No. 2010-108150”. In Patent Document 1, the shrinkage strain of the resin accompanying the phase change is calculated as a function of the linear hardening shrinkage coefficient and the reaction rate, and the shrinkage strain of the resin accompanying the resin temperature change is calculated as a function of the resin temperature and the linear expansion coefficient. The technology is disclosed.
Patent Document 2 discloses a technique for calculating a linear expansion coefficient according to a filler filling rate of a resin material and calculating a resin shrinkage strain.
Patent Document 3 “Japanese Patent Laid-Open No. 2003-91561” is cited as a patent document relating to a method for calculating foaming behavior in which bubbles are generated in a resin material. Patent Document 3 discloses a technique for calculating a behavior in which foaming occurs due to an exothermic reaction of a resin and the density of the entire resin decreases while flowing.

However,

Patent Documents

1, 2, and 3 do not calculate the viscosity coefficient and the elastic coefficient by the heat transfer calculation between the resin and the gas during the resin flow process.
For this reason, the calculation methods disclosed in

Patent Documents

1, 2, and 3 do not consider heat transfer with the gas when the resin is molded in contact with the solid surface as well as the gas. Since the increase in the viscosity coefficient and the elastic coefficient due to the temperature difference in the thickness direction cannot be calculated, the adhesion force between the resin and the solid cannot be predicted.

JP 2006-205740 A JP 2010-108150 A JP 2003-91561 A

When the resin material is molded in contact with the gas, the resin temperature decreases from the portion in contact with the gas due to heat transfer with the gas. At this time, when the resin is molded in contact with a solid as well as a gas, the resin temperature and the elastic modulus are distributed due to heat transfer from a portion of the resin in contact with the gas and the solid.

That is, the temperature of the resin portion in contact with the gas first decreases and the elastic modulus increases. For this reason, the resin part that comes into contact with the solid that shrinks and solidifies later is restrained from shrinking the resin toward the solid side due to the restraint at the resin part where the elastic modulus increases first, so the adhesion between the solid and the resin This causes a problem of lowering.

Therefore, the development of analysis technology that can predict the elastic coefficient accompanying the temperature change of the resin considering the heat transfer with the gas in the resin flow is an issue, and this analysis technology can be used to reduce the difference in the elastic coefficient of the resin. It is necessary to select the shape, mold structure and molding process conditions.

In order to solve the above problems, in the present invention, in the resin flow behavior calculation method in which the resin flow analysis device calculates the elastic coefficient distribution of the resin material molded in contact with the gas, (a) the space filled with the resin material Input a shape model and decompose it into three-dimensional solid elements based on the data. (B) Physical properties including at least density of resin material, thermal conductivity, specific heat, initial temperature of resin material, heat of resin and gas Enter boundary conditions including transmissibility, (c) input the elastic modulus of the resin as an equation including changes in the resin temperature, and (d) the continuity equation, Naviestokes equation, energy conservation equation, By calculating based on the elements, when calculating the resin temperature, speed, and pressure for each time step, the distribution of the elastic modulus of the resin input in step (c) is calculated, and (e) the above calculation is performed. Reach set time The contents including the elastic modulus of the resin of each element were output repeatedly until

In order to solve the above problems, in the present invention, in the resin flow behavior calculation method in which the resin flow analysis device calculates the elastic coefficient distribution of the resin material molded in contact with the gas, (a) the resin material is filled. A space shape model is input and decomposed into three-dimensional solid elements based on the data. (B) Physical properties including at least density of resin material, thermal conductivity, specific heat, initial temperature of resin material, resin and gas Enter boundary conditions including the heat transfer coefficient of (c) Enter the allowable value of the elastic coefficient difference of the resin material, (d) Enter the elastic coefficient of the resin as an equation including the change in resin temperature, (e) When calculating the resin temperature, speed, and pressure for each time step by calculating the continuous equation, Navi-Stokes equation, and energy conservation equation based on the 3D solid element, input in step (d) Modulus of resin (F) When the difference in elastic modulus of the resin calculated in step (e) is smaller than the allowable value input in step (c), the above calculation is repeated until the set time is reached. The contents including the elastic modulus of the resin of the element were output.

In order to solve the above problems, in the present invention, in the resin flow behavior calculation method in which the resin flow analysis device calculates the elastic coefficient distribution of the resin material molded in contact with the gas, (a) the resin material is filled. A space shape model is input and decomposed into three-dimensional solid elements based on the data. (B) At least the initial density of resin material, initial thermal conductivity, physical property values including specific heat, initial temperature of resin material, resin And the boundary condition including the heat transfer coefficient of gas, (c) 反応 Input the resin density as a function including the resin temperature or the reaction rate of the resin, and (d) the elastic modulus of the resin is an equation including the change of the resin temperature (E) When calculating the resin temperature, speed, and pressure for each time step by calculating the continuous equation, Navi-Stokes equation, and energy conservation equation based on the three-dimensional solid element, , Su Calculate the density of the resin entered in step (c) and the elastic modulus distribution of the resin entered in step (d), and (f) repeat the above calculation until the set time is reached. The contents including the coefficient and density are output.

According to the present invention, the product shape and the resin material 3 can reduce the difference in the elastic modulus of the resin in an arbitrary cross section in the resin cooling process by predicting the elastic modulus distribution of the resin in consideration of heat transfer with the gas in the resin flow. Material properties, cylinder structure, and molding process conditions can be optimized. That is, according to the present invention, cost reduction and development time reduction can be realized.

It is a schematic block diagram of the resin flow analysis apparatus of this invention. It is sectional drawing of the analysis object model used in the manufacturing process of the resin-coated wire mentioned in the Example as an analysis object example. It is a flowchart showing the process of the resin flow analysis process part in 1st embodiment of this invention. It is a flowchart showing the process of the resin flow analysis process part in 2nd embodiment of this invention. It is a figure which shows the calculation result of the temperature change over the outer periphery of the resin material of the analysis object model of FIG. It is a figure which shows the calculation result of the elastic coefficient change over the outer periphery of the resin material of the analysis object model of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

First, the molding process of the resin-coated wire material to be analyzed will be described with reference to FIG. A core wire 4 is disposed at the center of the cylinder 1, and a heated resin material 3 is disposed around the core wire 4. At the same time as the core wire 4 is moved and discharged from the cylinder outlet 2 in the direction of the arrow, the resin material 3 is extruded and integrated with the core wire 4 to flow.

The surface temperature of the resin material 3 decreases due to heat transfer from the air in the external space 7 (or any gas including nitrogen, oxygen, and carbon dioxide), and the resin material 3 has an outer peripheral portion 5 and an inner peripheral portion 6. Resin temperature difference occurs. Here, in the state where the elastic coefficient of the outer peripheral portion 5 where the resin temperature first decreases is increased, the temperature of the resin material 3 in the inner peripheral portion 6 decreases and contracts. At this time, since the elastic modulus of the resin in the outer peripheral portion 5 is high, the resin material 3 in the inner peripheral portion 6 is constrained by the resin material 3 in the outer peripheral portion 5 (pulled by the previously cured outer peripheral portion. (Condition). For this reason, there exists a problem that the adhesive force of the resin material 3 and the core wire 4 falls.
In the resin-coated wire forming step, the core wire 4 and the resin material 3 extruded from the cylinder 1 are cured in the air to form a resin-coated wire. For example, a wire winding (not shown) is taken up. Depending on the process, it will be wound on a roll.

The present invention calculates the temperature distribution of the resin by considering the heat transfer between the resin and the gas when the resin material is molded in contact with the gas, and calculates the resin from the obtained temperature distribution of the resin in an arbitrary cross section. We propose a calculation method that predicts the flow behavior of resin in detail.
When the resin material is molded in contact with the gas, the resin temperature decreases from the portion in contact with the gas due to heat transfer with the gas. At this time, when the resin is molded in contact with the solid surface as well as the gas, the resin temperature is distributed due to heat transfer from the resin gas and the portion in contact with the solid. Due to this resin temperature distribution, a difference in elastic modulus occurs, so that a difference also occurs in the adhesion between the resin and the solid. For this reason, it is necessary to predict the resin flow behavior reflecting the increase in the elastic modulus due to the temperature decrease of the resin.

Development of optimization of coating thickness of core wire 4 and resin material 3, optimization of molding process conditions such as resin temperature in cylinder, resin pressure, and physical properties of core wire 4 and resin material 3 through resin flow analysis Necessary for reducing costs and shortening the development period.

Here, the resin material 3 is a thermosetting resin such as epoxy or phenol, PPS (polyphenylene sulfide resin), PP (polypropylene resin), ABS (acrylonitrile butadiene styrene resin), PBT (polybutylene terephthalate resin), PE (polyethylene resin). ), PVC (polyvinyl chloride resin), PC (polycarbonate resin), PET (polyethylene terephthalate resin) and other thermoplastic resins can be used, and fillers such as glass, carbon, talc and mica can be used. It can also be filled in the resin.

Next, the resin flow analysis apparatus 100 used for predicting the flow behavior of the resin material 3 will be described. In FIG. 1, one example of the schematic block diagram of the resin flow analysis apparatus 100 of this invention is shown. The resin flow analysis apparatus 100 can be configured on a general-purpose computer, and the hardware configuration thereof includes a calculation unit 110 including a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read From a storage unit 120 composed of only memory (HDD), hard disk drive (HDD), etc., an input unit 130 composed of input devices such as a keyboard and a mouse, a display device such as an LCD (Liquid Crystal Display), and various output devices The output unit 140 includes a communication unit 150 including a NIC (Network Interface Card).
The communication unit 150 is connected to an external CAD device 170 and an external computer 180 via a network 160.

The calculation unit 110 implements the following functional units by loading and executing the resin flow analysis program 121 stored in the storage unit 120.
The resin flow analysis processing unit 111 is a main processing unit that executes a resin flow analysis by executing each processing unit according to an analysis target model and various parameters.

The model shape / element creation unit 112 generates an analysis target model that specifies the resin material 3 to be analyzed including the cylinder shape shown in FIG. 2, the shape of the core wire 4, and the region of the external space 7 via the input unit 130. It is created according to the input and stored in the analysis target model shape data storage area 122 of the storage unit 120. If the analysis target model is created in the external CAD device 170 or the external computer 180, the analysis target model is received from the CAD device 170 or the external computer 180 via the network 160, and the analysis target model shape is obtained. Store in the data storage area 122. Furthermore, finite element shape data is created from the analysis target model shape data and stored in the three-dimensional element data storage area 123.

The parameter / equation definition unit 113 presents an input guide screen to the output unit 140 in advance or at the time of analysis for the user, and material properties (initial viscosity of resin material, thermal conductivity, specific heat, core wire density, heat conduction) User inputs such as physical property values such as rate, specific heat, etc.), elastic coefficient formula, viscosity coefficient formula, exothermic formula, etc. are received from the input unit 130 and stored in the material physical property / equation storage area 124. Also, user input of boundary conditions to be analyzed such as resin material in the cylinder and initial temperature of the core wire is received from the input unit 130 and stored in the boundary condition data storage area 125. Further, user input of analysis parameters such as evaluation section coordinates and allowable elastic modulus difference in the evaluation section is received from the input unit 130 and stored in the analysis parameter data storage area 126. In addition, a user input such as continuous / Navi-Estokes / energy storage type is received from the input unit 130 and stored in the continuous / Navi-Estokes / energy storage type storage area 127 in advance.

The temperature change / velocity / pressure calculation unit 114 of the resin material performs heat transfer from the boundary of the external space 7 such as air and the core wire 4 to the resin material 3 with respect to the shape data of the finite element of the analysis target model, the resin material 3 Calculate the amount of change including temperature, speed, and pressure associated with heat generation.
The viscosity coefficient / elastic coefficient / reaction rate calculation unit 115 of the resin material reads out the elastic coefficient equation, the viscosity coefficient equation, and the heat generation equation, and the resin material 3 calculated by the temperature change / velocity / pressure calculation unit 114 of the resin material. The viscosity coefficient, elastic coefficient, and reaction rate are calculated by substituting the temperature, velocity, and pressure of each into the respective equations.
The analysis result output processing unit 116 displays or outputs the distribution of the elastic modulus E1 of each finite element in an arbitrary cross section of the analysis target model specified by the user to the output unit 140. The analysis result is also transmitted to the external computer 180.

Next, processing of the resin flow analysis processing unit 111 that has executed the resin flow analysis program 121 will be described with reference to the flowchart of FIG.
First, in the model shape creation step S1001, the analysis target model shape data 122 specified by the operator via the input device 130, that is, the cylinder 1 shape, the resin material 3, the core wire 4 shape, and the external space 7 (extruded from the cylinder). The shape data of the analysis target area of the space where the resin material covering the periphery of the core wire is in contact with air is read from the storage unit 120.

Next, in step S1002 for creating a three-dimensional solid element, the shape of the data read in model shape creating step S1001 is decomposed into a plurality of specific spaces (finite elements of a three-dimensional solid), and shape data (three-dimensional elements) Data).

Next, in the material physical property input step S1003, the initial viscosity, thermal conductivity, specific heat, elastic modulus equations (Equation 1) and (Equation 2) of the resin material 3, and the viscosity equation equations (Equation 12) to (Equation 15). ), A display prompting the operator to input physical property values including the exothermic formulas (Equation 6) to (Equation 9) is received, and these data are received from the input unit 130 and stored in the storage unit 120. In addition, the physical property value including the density, thermal conductivity, and specific heat of the core wire 4 is also input.

Α: reaction rate, t: time, t ′: conversion time, t ₀ : gelation time, T: temperature, P: pressure, ρ: density, ρ ₀ : initial density, u: flow velocity, g: gravitational acceleration , Η: viscosity, η ₀ : initial viscosity, C: specific heat, γ: shear rate, λ: thermal conductivity, dα / dt: reaction rate, E _∞ , E _k , τ _k , K _s1 , K _s2 , T _s _{_{, N α, K α, E}} α, K ρ1, K ρ2, K ρ3, E λ, N λ, a, b, d, e, f, h: material specific constant, Q: amount of heat generated up to an arbitrary time , Q _o : total calorific value until the end of the reaction, dQ / dt: exothermic rate.
Only the formulas not registered in the storage unit 120 are requested to input to the operator, and the entered formulas are registered.

Next, in boundary condition input step S1004, the initial temperature of the resin material 3 in the cylinder, the initial temperature of the core wire 4 in the cylinder, the initial temperature of the external space 7, the moving speed of the core wire 4, the extrusion speed of the resin material 3, and the external A display prompting the operator to input the boundary condition of the analysis target including the heat transfer coefficient between the air in the space 7 and the resin material 3 is performed, and data is received from the input unit 130.

Next, in step S1005, the coordinates of the evaluation cross section (the operator designates the cross section position, for example, the AA ′ cross section in FIGS. 2 (a) and 2 (b)) and the elastic coefficient difference in the evaluation cross section (the outer peripheral portion of the resin material). Accept the input of the tolerance value of the difference between the elastic modulus of the inner circumference and the inner circumference. Further, an analysis start instruction, an initial time increment, an analysis result output time, and an analysis end time tend are received from the operator.
Here, the analysis is performed by increasing a minute time and calculating a change for each time step, and the time increment indicates a time step interval.

In step S1006, based on the analysis start instruction from the operator, the continuous equation (Equation 3), the Naviestokes equation (Equation 4), and the energy conservation equation (Equation 5) stored in the storage unit 120 are called, The physical property values and core wires of the resin material 3 including the initial time increment, the elastic modulus equations (Equation 1), (Equation 2), and the viscosity coefficient equations (Equation 12) to (Equation 15) that have been accepted so far. Substituting the physical property value of 4 and the like, the contents including the heat, heat transfer from the boundary of the air and the core wire 4 to the resin material 3, and the temperature, speed, and pressure accompanying the heat generation of the resin material 3 are calculated. This calculation result is stored in the analysis result storage area 128 of the storage unit 120 in association with the position of the finite element. The heat transfer to the core wire 4 can also be calculated.
Here, the heat transfer coefficient h between the air in the external space 7 and the resin material 3 input in the boundary condition input step S1004 is, for example, λ (thermal conductivity of air) / h (heat Assuming that there is a hypothetical substance (air) having a thickness of transmission rate), the temperature outside λ / h is linked with the energy conservation equation (Equation 5) as the initial temperature of the external space 7 input in step S1004. Thus, the surface temperature of the resin material 3 can be calculated. Further, the surface temperature of the resin material 3 is calculated by interlocking the heat flow rate obtained from the product of the difference between the surface temperature of the resin material 3 and the initial temperature of the external space 7 and the heat transfer coefficient with the energy conservation equation (Equation 5). You can also.
In addition, u: flow velocity, P: pressure, ρ: density, g: acceleration of gravity, η: viscosity, C: specific heat, λ: thermal conductivity, T: temperature, Q: calorific value, γ: shear rate .

Next, in step S1007, the elastic modulus equations (Equation 1) and (Equation 2), the viscosity modulus equations (Equation 12) to (Equation 15), and the heat generation equations (Equation 6) to (Equation 9) are called. The temperature, speed, and pressure of the resin material 3 calculated in 1006 are represented by the elastic modulus equations (Equation 1) to (Equation 2), the viscosity coefficient equations (Equation 12) to (Equation 15), and the exothermic equation (Equation 6) to By substituting into (Equation 9), the viscosity coefficient, elastic coefficient, and reaction rate are obtained.
In the initial time increment of analysis (first step), the initial time is t0, the time increment Δt1 = t1-t0, and the contents including the pressure, temperature, and speed of the resin material are calculated in step S1006, and calculated in step S1006. In step S1007, the temperature, pressure, and speed of the resin material 3 are determined in accordance with the elastic modulus equations (Equation 1) and (Equation 2), the viscosity coefficient equations (Equation 12) to (Equation 15), and the heat generation equation (Equation 6) By substituting into (Equation 9), the viscosity coefficient η1, the elastic coefficient E1, and the reaction rate α1 in the first step are obtained. The elastic modulus E1 of each finite element in an arbitrary cross section is calculated and its distribution is obtained.
Here, the viscosity coefficient η1 obtained in step S1007 is used as a coefficient in step S1006 in the calculation of the second step at the next time increment.

In step S1008, the convergence of the calculation is determined. Convergence is determined by, for example, determining that the ratio of the speed and the element length (the length of the divided element, usually the representative length of the tetrahedron or hexahedron) is within a predetermined range as convergence. (Determining that there is a sufficient number of meshes necessary for the analysis in the amount of velocity movement in time increment). If it does not converge, the calculation in step S1006 is repeated, and if it does not converge even with a predetermined number of repetitions, it returns to one of steps S1001 to S1004. When returning to any one of steps S1001 to S1004, the operator is prompted for a designation input, and which step to return to is determined according to the operator's decision input.

If the calculation has converged, in step S1009, in the cross section input in step S1004, the elastic modulus difference of the resin calculated in step S1007 is smaller than the allowable elastic modulus difference input in advance in step 1005. Judgment is made. If the calculated value is larger than the allowable value, the process returns to one of steps S1001 to S1004. When returning to any one of steps S1001 to S1004, the operator is prompted for a designation input, and which step to return to is determined according to the operator's decision input.
If the calculated value is smaller than the allowable value, it is determined in step S1010 whether the analysis time is longer than the set analysis end time tend. If the determination is YES, the analysis is terminated and the determination is NO. In that case, the process returns to the calculation in step S1006, and the next time step is calculated.

As described above, in the second and subsequent steps, the same calculation is repeated until the analysis end time “tend” reaches the set analysis end time. In step S1010, the analysis is performed at the time when the analysis end time “tend” is reached. Terminate.
In step S1011, the contents including the elastic modulus can be output after the analysis is completed or at an arbitrary time when the output is set.

Next, the process of the resin flow analysis processing unit 111 that has executed the resin flow analysis program 121 will be described with reference to the flowchart of FIG. 4 according to the second embodiment of the present invention. In this embodiment, the analysis process takes into account the use of foamed resin.
First, in the model shape creation step S2001, the analysis target model shape data 122 specified by the operator via the input unit 130, that is, the shape data of the cylinder 1 shape, the resin material 3, the core wire 4 shape, and the external space 7 is stored. The data is read from the analysis target model shape data storage area 122 of the unit 120.
Next, in step S2002 for creating a three-dimensional solid element, the shape of the model shape data read in model shape creating step S2001 is decomposed into a plurality of specific spaces (three-dimensional solid finite elements), and finite element shape data (3 Dimensional element data) is created and stored in the three-dimensional element data storage area 123.

Next, in the material physical property input step S2003, the initial viscosity, initial thermal conductivity, specific heat, elastic modulus formulas (Equation 1) and (Equation 2) of the resin material 3, and the viscosity coefficient equations (Equation 12) to (Equation 2). 15), a display prompting the operator to input physical properties including the exothermic formula (Equation 6) to (Equation 9), the density equation (Equation 10), and the thermal conductivity equation (Equation 11). These data are received from 130 and stored in the material property / equation storage area 124 of the storage unit 120. In addition, the physical property value including the density, thermal conductivity, and specific heat of the core wire 4 is also input.
Further, the density formula (Equation 10) indicates the macroscopic density of the foamed resin. When bubbles are formed in the resin along with foaming, the density of the resin is decreased.

Next, in boundary condition input step S2004, the initial temperature of the resin material 3 in the cylinder, the initial temperature of the core wire 4 in the cylinder, the initial temperature of the external space 7, the moving speed of the core wire 4, the extrusion speed of the resin material 3, and the external A display for prompting the operator of the boundary condition to be analyzed including the heat transfer coefficient between the air in the space 7 and the resin material 3 is performed, and data is received from the input unit 130 and stored in the boundary condition data storage area 125.

Next, in step S2005, the difference between the evaluation section (the operator specifies the section position. For example, the AA ′ section in FIGS. 2A and 2B) and the modulus of elasticity in the evaluation section (the outer peripheral portion of the resin material). Accept the input of the tolerance value of the difference between the elastic modulus of the inner circumference and the inner circumference. Further, an analysis start instruction from the operator, an initial time increment, a time for outputting the analysis result, and an analysis end time tend are received and stored in the analysis parameter data storage area 126.
Here, the analysis is performed by increasing a minute time and calculating a change for each time step, and the time increment indicates a time step interval.

In step S2006, based on the analysis start instruction from the operator, the continuous equation (Equation 3), the Naviestokes equation (Equation 4), and the energy conservation equation stored in the material property / equation storage area 124 of the storage unit 120. Called (Equation 5) and received input so far, initial time increment, elastic modulus equations (Equation 1), (Equation 2), viscosity coefficient equations (Equation 12) to (Equation 15), exothermic equation (Equation 6) to (Equation 9), the density equation (Equation 10), the thermal conductivity equation (Equation 11), and the physical property value of the resin material 3, the physical property value of the core wire 4, etc. are substituted, and the air in the external space 7 and Contents including temperature, speed, and pressure accompanying heat transfer from the boundary of the core wire 4 to the resin material 3 and heat generation of the resin material 3 are calculated. This calculation result is stored in the analysis result storage area 128 of the storage unit 120 in association with the position of the finite element. The heat transfer to the core wire 4 can also be calculated.
Here, the heat transfer coefficient h between the air in the external space 7 and the resin material 3 input in the boundary condition input step S2004 is, for example, λ (thermal conductivity of air) / h (heat Assuming that there is a hypothetical substance (air) having a thickness of the transmission rate, the temperature outside λ / h is linked with the energy conservation equation (Equation 5) as the initial temperature of the external space 7 input in step 2004 Thus, the surface temperature of the resin material 3 can be calculated. Further, the surface temperature of the resin material 3 is calculated by interlocking the heat flow rate obtained from the product of the difference between the surface temperature of the resin material 3 and the initial temperature of the external space 7 and the heat transfer coefficient with the energy conservation equation (Equation 5). You can also.
In addition, u: flow velocity, P: pressure, ρ: density, g: acceleration of gravity, η: viscosity, C: specific heat, λ: thermal conductivity, T: temperature, Q: calorific value, γ: shear rate .

Next, as step S2007, the elastic modulus equations (Equation 1) and (Equation 2), the viscosity modulus equations (Equation 12) to (Equation 15), the exothermic equations (Equation 6) to (Equation 9), the density equation ( (Equation 10), the thermal conductivity equation (Equation 11) is called, and the velocity, temperature, and pressure of the resin material 3 calculated in step S2006 are expressed by the elastic modulus equations (Equation 1), (Equation 2), and the viscosity coefficient equation ( By substituting into Equations (12) to (15), exothermic equations (Equation 6) to (Equation 9), density equation (Equation 10), and thermal conductivity equation (Equation 11), viscosity coefficient, elastic modulus, density, Obtain thermal conductivity and reaction rate.

In the initial time increment of analysis (first step), the initial time is t0, the time increment Δt1 = t1-t0, the contents including the pressure, temperature, and speed of the resin material are calculated in step S2006, and calculated in step S2006. In step S2007, the temperature, pressure, and speed of the resin material 3 are determined by the elastic modulus equations (Equation 1) and (Equation 2), the viscosity coefficient equations (Equation 12) to (Equation 15), and the exothermic equation (Equation 6) By substituting (Equation 9), density equation (Equation 10), and thermal conductivity equation (Equation 11), the viscosity coefficient η1, elastic coefficient E1, density ρ1, thermal conductivity λ1, and reaction rate α1 in the first step are obtained. Ask. The elastic modulus E1 of each finite element in an arbitrary cross section is calculated and its distribution is obtained.
Here, the viscosity coefficient η1, the density ρ1, and the thermal conductivity λ1 are used as the coefficients in step S2006 in the calculation of the second step at the next time increment.

In step S2008, calculation convergence is determined. Convergence is determined by, for example, determining that the ratio of the speed and the element length (the length of the divided element, usually the representative length of the tetrahedron or hexahedron) is within a predetermined range as convergence. (Determining that there is a sufficient number of meshes necessary for the analysis in the amount of velocity movement in time increment). If it does not converge, the calculation in step S2006 is repeated, and if it does not converge even at a predetermined number of repetitions, the process returns to any of steps S2001 to S2004. When returning to any one of steps S2001 to S2004, the operator is prompted for a designation input, and which step to return to is determined according to the operator's decision input.

When the calculation converges, in step S2009, the difference in the elastic modulus of the resin calculated in step S2007 (the difference in elastic modulus between the outer peripheral portion and the inner peripheral portion of the resin material) in step S2004 is obtained in step S2004. It is determined whether it is smaller than the allowable value of the elastic coefficient difference inputted in advance. If the calculated value is larger than the allowable value, the process returns to one of steps S2001 to S2004. When returning to any one of steps S2001 to S2004, the operator is prompted for a designation input, and which step to return to is determined according to the operator's decision input.
If the calculated value is smaller than the allowable value, it is determined in step S2010 whether the analysis time is longer than the set analysis end time tend. If the determination is YES, the analysis is terminated and the determination is NO. In the case, the calculation returns to step S2006 and the next time step is calculated.

As described above, in the second and subsequent steps, the same calculation is repeated until the analysis time reaches the set analysis end time tend. In step S2010, the analysis is performed at the time when the analysis time reaches the set analysis end time tend. Terminate.
In step S2011, the content including the elastic modulus can be output after the analysis is completed or at an arbitrary time when the output is set.

In addition, the equation of the elastic coefficient is not limited to (Equation 1) and (Equation 2), and any equation including the temperature of the resin material 3 can be used.
The exothermic equation is not limited to (Equation 6) to (Equation 9), and any function including the reaction rate of the resin material 3 can be used. When the resin material 3 that does not generate heat is used, Calculation can be omitted.
The viscosity equation is not limited to (Equation 12) to (Equation 15), and an arbitrary function including the temperature or reaction rate of the resin material 3 can be used, and calculation with a constant value can also be performed. To do.

The density equation is not limited to (Equation 10), and an arbitrary function including the temperature or reaction rate of the resin material 3 or the resin pressure can be used, and calculation with a constant value can also be performed.
The thermal conductivity formula is not limited to (Equation 11), and an arbitrary function including the temperature or density of the resin material 3 can be used, and calculation with a constant value can also be performed.
The specific heat can also be used as a function including the temperature of the resin material 3. The gas in the external space 7 is not limited to air but can be any gas including nitrogen, oxygen, and carbon dioxide, and the convergence determination can be performed using any determination method.
Further, not only three-dimensional analysis but also two-dimensional analysis can be performed. The above calculation can be performed using the finite element method, the finite volume method, or the finite difference method.

Below, the example of the analysis using the flowchart shown in FIG. 4 is shown.
Here, the resin material 3 and the core wire 4 extruded from the cylinder 1 shown in FIG. 2 were analyzed. The resin material 3 is extruded in the arrow direction, and the core wire 4 is also moved in the arrow direction. Here, the diameter of the resin material 3 is Φ20 mm, the diameter of the core wire 4 is Φ10 mm, the time immediately after being extruded from the cylinder 1 is 0 s, and the resin of the AA ′ cross section (cross section orthogonal to the core wire 4) shown in the figure The time change of the temperature of the material 3 and the core wire 4 was calculated.

The heat transfer calculation of the resin material 3 and the core wire 4 accompanied by the density change due to the resin heat generation in consideration of the heat transfer to the air in the external space 7 with the coating thickness, the thermal conductivity, and the specific heat of the resin material 3 being constant. Went. The temperature of the air in the external space 7 is 298.15K, the core wire moving speed is 1mm / s, the heat transfer coefficient between the air in the external space 7 and the resin material 3 is 20W / m ² · K, and the total calorific value Q0 is 51000J / kg. And

Table 1 shows the physical properties of air and the initial temperature of the resin material 3, the core wire 4, and the external space 7. In addition, since the density of the resin material 3 calculates the change accompanying foaming, the value of Table 1 represents the initial value.

Here, the equation of elastic modulus used (Expression 16) as a function of the resin temperature.

In (Equation 16), E1, E2, E3, and E4 are constants specific to the resin material 3.
The equation of viscosity coefficient is (Equation 12) to (Equation 15), the exothermic equation is (Equation 6) to (Equation 9), and the density equation is (Equation 10).
The elastic modulus equation (Equation 16) is shown in Table 2, the viscosity coefficient equation is (Equation 12) to (Equation 15) in Table 3, and the exothermic equations (Equation 6) to (Equation 9) are given. Table 4 shows the coefficients of the density equation (Equation 10).

In addition, the allowable value of the elastic coefficient difference (the difference in elastic coefficient between the outer peripheral portion 5 and the inner peripheral portion 6 of the resin material 3) in the evaluation cross section (FIG. 2B) is 5 GPa, and the calculation time is 60 s. Here, in the radial direction of the core wire 4 and the resin material 3, when the position of the inner periphery 6 (position in contact with the solid) of the resin material 3 is 0 mm and the position of the outer periphery 5 is 5 mm, 20, 40, 60 s Later resin temperature and elastic modulus distributions were calculated. The results are shown in FIGS.
As shown in FIG. 5, the resin temperature decreases with time and approaches a constant value. As shown in FIG. 6, although the value of the elastic coefficient changes with the resin temperature change, it can be understood that the elastic coefficient can be calculated to be smaller than 5 GPa set as the allowable value of the elastic coefficient difference in the evaluation section.

By using the elastic modulus calculation method of the resin material 3 described above, the difference in elastic modulus in the evaluation cross section is made smaller than an allowable value (for example, the resin coating does not easily peel off the core wire). Product shape (core wire thickness 4 and resin material 3 coating thickness), resin material 3 and material properties of core wire 4 and molding process conditions (heat transfer rate, initial temperature, etc.) can be evaluated.

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Cylinder exit 3 Resin material 4 Core wire 5 Outer periphery of resin material 6 Inner periphery of resin material 7 External space 100 Resin flow analysis device 110 Calculation unit 111 Resin flow analysis processing unit 112 Model shape / element creation unit 113 Parameter / equation definition Unit 114 temperature change / velocity / pressure calculation unit 115 resin material viscosity coefficient / elastic coefficient / reaction rate calculation unit 116 analysis result output processing unit 120 storage unit 121 resin flow analysis program storage region 122 analysis target model shape data storage Area 123 Three-dimensional element data storage area 124 Material property / equation storage area 125 Boundary condition data storage area 126 Analysis parameter data storage area 127 Continuous / Navi Stokes / energy storage type storage area 128 Analysis result storage area 130 Input unit 140 Output unit 150 Communication unit 160 Net Over click 170 CAD apparatus 180 external computer

Claims

A resin flow behavior calculation method in which a resin flow analysis device calculates an elastic coefficient distribution of a resin material molded in contact with a gas,
(A) Input a shape model of the space filled with the resin material, and decompose it into three-dimensional solid elements based on the data,
(B) Enter the boundary conditions including at least the density of the resin material, the thermal conductivity, the physical property value including the specific heat, the initial temperature of the resin material, and the heat transfer coefficient between the resin and gas,
(C) Enter the elastic modulus of the resin as an equation that includes changes in the resin temperature,
(D) When calculating the resin temperature, speed, and pressure for each time step by calculating the continuous equation, Navi-Stokes equation, and energy conservation equation based on the three-dimensional solid element, the step (c ) To calculate the distribution of the elastic modulus of the resin entered in
(E) A resin flow behavior calculation method comprising the steps of repeating the above calculation until a set time is reached and outputting contents including the elastic modulus of the resin of each element.
A resin flow behavior calculation method in which a resin flow analysis device calculates an elastic coefficient distribution of a resin material molded in contact with a gas,
(A) Input a shape model of the space filled with the resin material, and decompose it into three-dimensional solid elements based on the data,
(B) Enter the boundary conditions including at least the density of the resin material, the thermal conductivity, the physical property value including the specific heat, the initial temperature of the resin material, and the heat transfer coefficient between the resin and gas,
(c) Enter the allowable elastic modulus difference of the resin material,
(D) Enter the elastic modulus of the resin as an equation that includes changes in the resin temperature,
(E) When calculating the resin temperature, speed, and pressure for each time step by calculating a continuous equation, Navi-Stokes equation, and energy conservation equation based on the three-dimensional solid element, the step (d ) To calculate the distribution of the elastic modulus of the resin entered in
(F) When the difference in the elastic modulus of the resin calculated in step (e) is smaller than the allowable value input in step (c), repeat the above calculation until the set time is reached, and the elasticity of the resin of each element A method for calculating a resin flow behavior, comprising each step of outputting contents including a coefficient.
A resin flow behavior calculation method in which a resin flow analysis device calculates an elastic coefficient distribution of a resin material molded in contact with a gas,
(A) Input a shape model of the space filled with the resin material, and decompose it into three-dimensional solid elements based on the data,
(B) At least the initial density of the resin material, the initial thermal conductivity, the physical property value including the specific heat, the initial temperature of the resin material, the boundary conditions including the heat transfer coefficient of the resin and gas,
(c) Enter the resin density as a function including the resin temperature or resin reaction rate,
(D) Enter the elastic modulus of the resin as an equation that includes changes in the resin temperature,
(E) When calculating the resin temperature, speed, and pressure for each time step by calculating a continuous equation, Navi-Stokes equation, and energy conservation equation based on the three-dimensional solid element, the step (c ) Calculate the density of the resin entered in step) and the elastic modulus distribution of the resin entered in step (d)
(F) A resin flow behavior calculation method comprising the steps of repeating the above calculation until a set time is reached and outputting contents including the elastic modulus and density of the resin of each element.
In the calculation method of the resin flow behavior according to any one of claims 1 to 3,
In step (a), a solid space shape model is further input, in step (b), the solid moving speed is further set, and the solid material input in step (a) is contacted and molded. A method for calculating a resin flow behavior, comprising: steps for outputting contents including an elastic modulus of the resin in the case of performing.
In the calculation method of the resin flow behavior according to claim 3,
Enter the allowable value of the difference in resin elastic modulus,
When the difference in the elastic modulus of the resin calculated in step (e) is smaller than the input allowable value, the calculation is repeated until the set time is reached, and the contents including the elastic modulus of the resin of each element are output. And a resin flow behavior calculation method characterized by comprising:
In the calculation method of the resin flow behavior according to any one of claims 1 to 3,
In the step (b), an exothermic reaction formula of the resin is further input, and the resin flow behavior calculation method is characterized.
In the calculation method of the resin flow behavior according to any one of claims 1 to 3,
In the step (b), a resin flow behavior calculation method further comprising inputting a thermal conductivity formula of the resin.
A calculation program for resin flow behavior for causing a computer to execute a procedure for calculating an elastic coefficient distribution of a resin material molded in contact with a gas,
(A) A procedure for inputting a shape model of a space filled with a resin material and decomposing it into a three-dimensional solid element based on the data;
(B) a procedure for inputting boundary conditions including at least the density of the resin material, the thermal conductivity, the physical property value including the specific heat, the initial temperature of the resin material, and the heat transfer coefficient between the resin and gas;
(C) a procedure for inputting the elastic modulus of the resin as an equation including a change in the resin temperature;
(D) When calculating the resin temperature, speed, and pressure for each time step by calculating the continuous equation, Navi-Stokes equation, and energy conservation equation based on the three-dimensional solid element, the procedure (c ) To calculate the elastic modulus distribution of the resin entered in
(E) A resin flow behavior calculation program characterized in that the above calculation is repeated until the set time is reached, and each procedure for outputting contents including the elastic modulus of the resin of each element is executed.
In the calculation program of the resin flow behavior according to claim 8,
Prior to the step (d), a step (f) for inputting the resin density as a function including the resin temperature or the reaction rate of the resin is added,
When calculating the resin temperature, velocity, and pressure for each time step by calculating the continuous equation, Naviestokes equation, energy conservation equation based on the three-dimensional solid element, the procedure (d) In place of the procedure for calculating the resin density entered in step (f), the elastic modulus distribution of the resin entered in step (c), and in step (e), the above calculation reaches the set time. The resin flow behavior calculation program is characterized in that each procedure is executed instead of outputting the contents including the elastic modulus and density of the resin of each element.
In the calculation program of the resin flow behavior according to claim 8 or claim 9,
Prior to the step (d), a procedure (g) for inputting an allowable value of the elastic modulus difference of the resin material is added,
The procedure (e) is repeated until the set time is reached when the difference in elastic modulus of the resin calculated in the procedure (d) is smaller than the allowable value input in the procedure (g). A resin flow behavior calculation program characterized in that each procedure is executed instead of a procedure for outputting contents including the elastic modulus and density of the resin of the element.