Know your materials

Polymer Melt Rheology: A guide for Industrial Practice: Book Review

April 15, 1994•by DatapointLabs•5,484 views

Two approaches to polymer processing rheology are discernible; by theoreticians. who are concerned with a fundamental description of what would be happening if certain idealized criteria are met; and by practitioners, who are concerned with the results of what is actually happening.” In his newly revised book, Mr. Cogswell skillfully treads the middle ground between these camps, providing an interesting, informative guide to rheology for the design engineer.

Methodology for Selection of Material Models for Plastics Impact Simulation

May 19, 2006•by DatapointLabs•5,483 views

The volume of plastics that are subjected to impact simulation has grown rapidly. In a previous paper, we discussed why different material models are needed to describe the highly varied behavior exhibited by these materials. In this paper, we cover the subject in more detail, exploring in depth, the nuances of commonly used LS-DYNA material models for plastics, covering important exceptions and criteria related to their use.

The Influence of Permanent Volumetric Deformation on the Reduction of the Load Bearing Capability of Plastic Components

July 22, 2015•by Paul Du Bois•5,466 views

"During the past years polymer materials have gained enormous importance in the automotive industry. Especially their application for interior parts to help in passenger safety load cases and their use for bumper fascias in pedestrian safety load cases have driven the demand for much more realistic finite element simulations. For such applications the material model 187 (i.e. MAT_SAMP-1) in LS-DYNA® has been developed. In the present paper the authors show how the parameters for the rather general model may be adjusted to allow for the simulation of crazing effects during plastic loading. Crazing is usually understood as inelastic deformation that exhibits permanent volumetric deformations. Hence a material model that is intended to be applied for polymer components that show crazing effects during the experimental study, should be capable to produce the correct volumetric strains during the respective finite element simulation. The paper discusses the real world effect of crazing, the ideas to capture these effect in a numerical model and exemplifies the theoretical ideas with a real world structural component finite element model."

Injection Molding Handbook: Book Review

January 17, 1994•by DatapointLabs•5,444 views

This book, edited by the Wisconsin based team of Osswald, Turng and Gramman, represents a compilation of work by several well known authors and brings together a body of knowledge that will be appreciated by injection molding professionals and students of plastics processing.

Improving Simulation Quality with Reliable Materials Methods

April 1, 2019•by DatapointLabs•5,415 views

Keynote address delivered at NAFEMS seminar on "Material Properties in Structural Calculation: Modeling, Calibration, Simulation & Optimization."

Using the PRF Model for Polypropylene

April 28, 2015•by Tod Dalrymple•5,411 views

Successful Injection Molding: Book Review

November 9, 2002•by DatapointLabs•5,401 views

There has been a long standing need for a book that describes the process of injection molding using the insights developed from twenty years of computer aided engineering (CAE). The authors, all veterans of injection molding CAE, have filled this need with their book. "Successful Injection Molding" is a lot more than a book about injection molding CAE. It is clear at this stage that CAE is a tool, which, if well handled, can provide excellent results. That being said, a successful implementer of CAE for injection molding must have a range of insights into the diverse idiosyncrasies of this enormously complex manufacturing process. The book is successful in clearly addressing these issues.

Numerical and Experimental Investigation of Elongational Viscosity effects in a Coat-Hanger Die

June 9, 2015•by PolyXtrue•5,394 views

The flow in a coat-hanger die is simulated using the axisymmetric and planar elongational viscosities of a low-density polyethylene (LDPE) resin. Elongational viscosity is found to affect the velocity distribution at the die exit. Also, the predicted pressure drop in the die changed significantly when the effect of elongational viscosity was included in the simulation. However, elongational viscosity had only a minor effect on the temperature distribution in the die. Predicted pressure drop is compared with the corresponding experimental data.

Principles of Polymer Engineering, 2nd Edition: Book Review

August 14, 1997•by DatapointLabs•5,377 views

This book presents a concise and easily readable introduction to polymer behavior for design and production engineers. It seeks to explain the behavior of plastics and rubber using a materials science framework, by relating observed phenomena to changes in morphological and molecular structure. This presents a powerful way for engineers to grasp the underlying factors that make polymers the complex materials that they are. The reader is encouraged to step away from using linear-elastic metals concepts when designing with plastics. The pitfalls of such simplifications are pointed out and guidelines are presented to aid the designer in adopting a non-linear approach.

Prediction of the Plastic Component Parts Durability with Use of a Drop Test Simulation

May 6, 2016•by Megan Lobdell•5,373 views

I found this to be a good explanation of calculating linear Drucker Prager variables for Abaqus.