Computation of Die Swell behind a Complex Profile Extrusion Die Using a Stabilized Finite Element Method for Various Thermoplastic Polymers

使用稳定有限元方法计算各种热塑性聚合物复杂轮廓挤出模具后面的模具膨胀

• 批准号: 184122738
• 负责人: Professor Marek Behr, Ph.D.
• 金额: --
• 依托单位: Institut für Leichtbau und Struktur-Biomechanik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/184122738?language=en
• 关键词: Computation; Die; Swell; behind; Complex

The design of plastics-extrusion dies continues to rely on both experimental studies and the experience of the die designer. Direct die design is in general not possible; reason being the highly non-linear behavior of the plastics melt - a factor strongly tied to its viscoelastic properties. The latter cause the melt to swell severely and non-uniformly when exiting the shape-defining zone of the die. This final geometry of the product may resemble neither the size, nor the key features of the outflow die geometry. Considering the costly and time-consuming experiments that are presently needed in die design, it is advantageous to be able to predict the die swell behind industrially relevant extrusion dies on the basis of computational modelling. In this project, a suitable finite-element method is being developed. Regarding the modeling of the material properties, the focus rests on materials that can be represented by the Oldroyd-B model (e.g., LDPE or HDPE). The newly developed method focuses on two main ingredients: a stabilized discretization method and a boundary-conforming, highly resolved free-surface treatment capable of presenting die swell ratios of - after the first project phase - up to 170%.

塑料挤压模具的设计继续依赖于实验研究和模具设计师的经验。直接设计模具通常是不可能的；原因是塑料熔体的高度非线性行为，这是与其粘弹性特性密切相关的一个因素。后者导致熔体在离开模具定形区时发生严重且不均匀的膨胀。该产品的最终几何形状可能既不类似于尺寸，也不类似于流出模具几何形状的关键特征。考虑到目前模具设计中需要进行昂贵和耗时的实验，在计算建模的基础上能够预测工业相关挤压模具后的模具膨胀是有利的。在这个项目中，一种合适的有限元方法正在开发中。关于材料属性的建模，重点在于可以用oldyd - b模型表示的材料（例如，LDPE或HDPE）。新开发的方法侧重于两个主要组成部分：稳定的离散化方法和符合边界的高分辨率自由表面处理，能够在第一个项目阶段后呈现高达170%的模具膨胀率。

项目成果

Automatic implementation of material laws: Jacobian calculation in a finite element code with TAPENADE

自动实现材料定律：使用 TAPENADE 在有限元代码中进行雅可比计算

• DOI: 10.1016/j.camwa.2016.10.010
• 发表时间: 2016
• 期刊: ArXiv
• 作者: Zwicke;Knechtges;Elgeti
• 通讯作者: Elgeti

Space‐time NURBS‐enhanced finite elements for free‐surface flows in 2D

时空 NURBS™ 二维自由表面流的增强有限元

• DOI: 10.1002/fld.4189
• 发表时间: 2016
• 期刊: International Journal for Numerical Methods in Fluids
• 影响因子: 1.8
• 作者: Stavrev;Knechtges;Elgeti;S. Huerta
• 通讯作者: S. Huerta

An ultraweak DPG method for viscoelastic fluids

粘弹性流体的超弱 DPG 方法

• DOI: 10.1016/j.jnnfm.2017.06.006
• 发表时间: 2017
• 期刊: Journal of Non-newtonian Fluid Mechanics
• 影响因子: 3.1
• 作者: Knechtges;Roberts;Elgeti;Demkowicz
• 通讯作者: Demkowicz

The fully-implicit log-conformation formulation and its application to three-dimensional flows

• DOI: 10.1016/j.jnnfm.2015.07.004
• 发表时间: 2015-09-01
• 期刊: JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
• 影响因子: 3.1
• 作者: Knechtges, Philipp