Method and apparatus for simulating plastic material flowing through extruding channel

Patent metadata

Field	Value
Publication number	US-9378307-B2
Application number	US-201213690192-A
Country	US
Kind code	B2
Filing date	Nov 30, 2012
Priority date	Mar 7, 2012
Publication date	Jun 28, 2016
Grant date	Jun 28, 2016

Abstract

A computerized method for simulating a plastic material flowing through an extruding channel comprises a step of making a flow calculation. The flow calculation includes: a primary calculation based on the plastic material model provided with a viscosity which is constant; a secondary calculation based on the plastic material model which is provided with a viscosity having a shear-velocity dependency or alternatively a temperature dependency, and whose initial values are set to those of the material model calculated in the primary calculation step; and a third calculation based on the material model which is provided with a viscosity having both of the shear-velocity dependency and the temperature dependency, and whose initial values are set to those of the material model calculated in the secondary calculation step.

First claim

The invention claimed is:

1. A computerized method for simulating a plastic material having a viscosity having a shear-velocity dependency and a temperature dependency and flowing through an extruding channel having a variable cross-sectional area and an input port and an output port for the plastic material, comprising
defining a material model of the plastic material,
generating a channel model which is a finite element model of the extruding channel,
defining the material model in a portion of the channel model corresponding to the internal space of the extruding channel,
making a flow calculation for a flow of the material model from the input port to the output port,
wherein said step of making the flow calculation includes
setting a constant viscosity to the material model to define a primary material model, and making a primary calculation in which the flow calculation for the primary material model is made until the flow of the primarily material model becomes stable to obtain calculated values on the primarily material model,
setting, as initial values, the calculated values obtained in the primary calculation together with the viscosity as having a shear-velocity dependency or alternatively a temperature dependency to the material model to define a secondary material model, and making a secondary calculation in which, the flow calculation for the secondary material model is made until the flow of the secondary material model becomes stable to obtain calculated values on the secondary material model, and
setting, as initial values, the calculated values obtained in the secondary calculation together with the viscosity as having both of the shear-velocity dependency and the temperature dependency to the material model to form a third material model, and making a third calculation in which the flow calculation for the third material model is made until the flow for the third material model becomes stable,

acquiring, from the stably-flowing third material model, physical quantities of the plastic material, wherein the physical quantities include the velocity, pressure and temperature, and
judging whether the plastic material flowing out from the extruding channel is good or not based on the acquired physical quantities,
wherein when judged as not good, a configuration of the extruding channel is modified, and the step of generating a channel model and the subsequent steps are again performed, and
when judged as good, a three-dimensional configuration of the channel model is used to actually design the extruding channel.

2. The method according to claim 1 , wherein
the material model includes a first material model and a second material model having different viscosities, and
in the flow calculation, a multiphase flow of the first material model and the second material model is calculated based on a volume of fluid (VOF) method.

3. The method according to claim 2 , wherein
the flow calculation is made in two steps: a first step in which the flow calculation is made on the first material model only; and a second step which is made after the first material model becomes a stable state, and in which the flow calculation is made on the first material model as well as the second material model gradually supplied from the input port.

4. The method according to claim 3 , wherein
the channel model comprises a first channel model on which the first material model is defined, and a second channel model on which the second material model is defined, and
the second channel model joins the first channel model in a downstream side so that the first material model and the second material model flow together to form said multiphase flow.

5. The method according to claim 2 , wherein
the channel model comprises a first channel model on which the first material model is defined, and a second channel model on which the second material model is defined, and
the second channel model joins the first channel model in a downstream side so that the first material model and the second material model flow together to form said multiphase flow.

6. The method according to claim 2 , wherein
in the step of judging whether the plastic material flowing out from the extruding channel is good or not, the criteria of the judgment are (a) the flow velocity distribution is uniform at the output port, (b) the material models having the different viscosities are distributed at the output port as desired, and (c) the temperature distribution in the flow becomes uniform, and if at least one of the criteria is not satisfied, the plastic material flowing out from the extruding channel is judged as being not good.

7. The method according to claim 1 , wherein
the material model includes a first material model and a second material model having different viscosities,
the channel model comprises a first channel model in which the first material model is defined, and a second channel model in which the second material model is defined,
wherein the second channel model joins the first channel model in a downstream side so that the first material model and the second material model flow together to form a multiphase flow, and
in the flow calculation, the multiphase flow of the first material model and the second material model is calculated based on a volume of fluid (VOF) method.

Assignees

• Sumitomo Rubber Ind

Inventors

• Tsunoda Masaya
• Tanimoto Ryosuke

Classifications

• G06F17/5018

  Physics · mapped topic

• G06F17/50 Primary

  Physics · mapped topic

• G06F30/23 Primary

  using finite element methods [FEM] or finite difference methods [FDM] · CPC title

• G06F30/28 Primary

  using fluid dynamics, e.g. using Navier-Stokes equations or computational fluid dynamics [CFD] · CPC title

• G06F30/00

  Computer-aided design [CAD] · CPC title