POLYMERIC COMPOSITE MATERIALS

1
??? ???? ?????? ??????
??? ?? ?????????? ?????? ????? ????????????
???????? ? ?????? ????????????? ????????? ?????
????????????

????? 13-14
2
STRUCTURAL JOINTS
IN

• POLYMERIC COMPOSITE MATERIALS

By Hossam Sallam, Ph.D. Zagazig University
3
Objectives

• The main goal of this review article is to
  present a sound background regarding the
  development of the understanding of the
  mechanical behavior and the failure modes of the
  mechanically fastened, snap, bonded, and hybrid
  joints in polymeric composite materials.

4
LAYOUT

• INTRODUCTION
• JOINTS ------ COMPOSITES
• MECHANICALLY FASTENED JOINTS
• Kt ------ FAILURE MODES
• SNAP JOINTS
• BONDED JOINTS
• Fusion Bonding for Joining Thermoplastic Matrix
  Composites
• ADHESIVE BONDED SIMILAR/DISSIMILAR MATERIALS.
• HYBRID JOINTS

5
Introduction
STRUCTURAL JOINTS
6
Introduction
COMPOSITE MATERIALS
Classification Of Composite Materials
W.R.T Reinforcement Forms
W.R.T Type of Matrix

• Particle

• Polymers

• Metals

• Fiber

Discontinuous

• Ceramics

Continuous

• Laminate

7
(No Transcript)
8
out line

• INTRODUCTION
• MECHANICALLY FASTENED JOINTS
• SNAP JOINTS
• BONDED JOINTS
• HYBRID JOINTS
• CONCLOUSIONS

9
MECHANICALLY FASTENED JOINTS

• Single lap bolted joint

Double Strap bolted joint
10
Types of Circular Hole in Tensioned FRP Plates

• OPEN-HOLE TENSION

• FILLED-HOLE TENSION WITH/WITHOUT A CLAMP-UP LOAD.

• BOLTED JOINT, BOLT-LOADED HOLE WITH/WITHOUT
  CLAMP-UP LOAD.

11
FAILURE MODES OF TENSION PLATES
OPEN-HOLE
Fiber Breakage Matrix Cracking
Delamination
Fiber-Matrix Splitting
12
FAILURE MODES OF
BOLTED JOINTS
sf/ s?o 0.8 Steel
sf/ s?o lt 0.5 FRP
Net-Tension
s?N P /(W-dHt)
Shear-Out
s?SO PSO /(2et)
Transverse
splitting
Cleavage
Bearing
Pull-out
s?b P /(dBt)
13
out line

• INTRODUCTION
• MECHANICALLY FASTENED JOINTS
• SNAP JOINTS
• BONDED JOINTS
• HYBRID JOINTS
• CONCLOUSIONS

14
SNAP JOINTS
15
SNAP JOINTS

(a) Composite Transmission Tower (b) Truss
Joint
16
out line

• INTRODUCTION
• MECHANICALLY FASTENED JOINTS
• SNAP JOINTS
• BONDED JOINTS
• HYBRID JOINTS
• CONCLOUSIONS

17
Fusion Bonding Techniques
Bulk Heating
Frictional Heating
Electromagnetic Heating
Two-stage Techniques
Induction Welding Microwave Heating
Dielectric Heating Resistance Welding
Hot Plate Welding Hot Gas Welding Radiant
Welding
Co-consolidation Hot-melt Adhesives Dual Resin
Bonding
Spin Welding Vibration Welding Ultrasonic
Welding
Infrared Welding Focused Infrared Welding
Laser Welding Solar Energy
18
BONDED JOINTS
ADHESIVE-1

• Single lap

• Double lap

• Double strap

19
BONDED JOINTS
ADHESIVE-2
Stepped lap
Double stepped lap
Single scarf
Double scarf
20
BONDED JOINTS
ADHESIVE-3
AL6XN steel
T700 carbon/epoxy
The general geometric parameters for a
tongue-and-groove joint.
New design with flat, pointed inserts
Wavy-lap joint main dimensions
21
Prevention of failure in Adhesive
Joints
Peeling
Bead end (if possible)
Increase area
Rivet, bolt or spot weld
Increase stiffness
22
out line

• INTRODUCTION
• MECHANICALLY FASTENED JOINTS
• SNAP JOINTS
• BONDED JOINTS
• HYBRID JOINTS
• CONCLOUSIONS

23
HYBRID JOINTS
Retrofitting schemes
24
out line

• INTRODUCTION
• MECHANICALLY FASTENED JOINTS
• BONDED JOINTS
• SNAP JOINTS
• HYBRID JOINTS
• CONCLOUSIONS

25
CONCLUSIONS

• All joining methods present advantages and
  drawbacks, and they may be more or less suitable
  to particular application depending on its
  specific requirements.
• Well-established joining technologies for
  metallic structures are not directly applicable
  to FRP.
• Some adhesives are disposed to degradation by
  temperature and humidity.
• Hybrid joints give better static as well as
  fatigue performance than adhesive joints in
  composites.

26
??????
????? ??? ?? ????????