文档介绍：Drilling of Fiber-Reinforced Plastics - Tool Modeling
and Defect Prediction
Athulan Vijayaraghavan
January 23, 2006
Abstract
Fiber reinforced polymer (FRP) composites have been steadily replacing metals as choice
engineering materials for various applications. Although FRPs can be manufactured to
shape, post processing operations such as machining are required to create some
features (such as holes). In order to drill holes efficiently with the least waste and defects,
it is essential to understand the machining behavior of FRPs. As FRPs are multiphase
materials plex load-response behavior, there is a need to turn to analytical and
numerical approaches to fully understand the machining process. This report discusses
a model to analytically estimate the edge defect in drilled FRP laminates. The model
predicts that increasing drilling thrust force causes greater delamination and thus, greater
edge defects. The report also discusses a tool which can create automated 3D CAD drill
models based on geometric as well as manufacturing parameters. This tool is a required
component of numerical/FE-models of FRP drilling. The tool outputs the drill in a variety
of solid geometry formats which can then be meshed and used in different FE analysis
packages.
Contents
1 Introduction 3
What are posites? . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
FRPs and the Aerospace Industry . . . . . . . . . . . . . . . . . . . . . . . . 5
Need for a Modeling Approach . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Report Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2 Challenges in Modeling FRP Machining 9
Finite Element Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
FRP Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Failure Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Failure Growth and Crac