Review of multifunctional composites in automotive applications

Rujie Sun

www.bris.ac.uk/composites

2/12Content

• Background and Introduction

• Fundamentals of multifunctional composites

• Applications of multifunctional composites in automotive

industry

• Conclusions

3/12Background and Introduction

Fig. 1. The published items related to the automotive application of composite materials(a), and multifunctional composite materials (b). Data is based on the report of Web ofScience.

(a) (b)

4/12Fundamentals of multifunctional composites

• Shape memory polymer composites

Fig. 2. Schematic of shape-memory effect during a typical thermomechanical cycle.

Shape memory polymers (SMPs) are stimuli-responsive materialsthat can recover to its original shape after a large deformationupon the application of external stimulus.SMPs can be activated by heat, magnetism, electricity, light,moisture, and even certain chemical stimulus (e.g., a change inpH value), etc.

Source: Leng J, Lan X, Liu Y, et al. Progress in Materials Science, 2011, 56(7): 1077-1135.

5/12Fundamentals of multifunctional composites

Fig. 3. Comparisons of three main self-healing methods: (a) capsule-based, (b) vascular, and (c) intrinsic methods .

• Self-healing polymer composites

Source: Blaiszik B J, Kramer S L B, Olugebefola S C, et al. Annual Review of Materials Research, 2010, 40: 179-211.

6/12Fundamentals of multifunctional composites

• Green composites

The reinforcement element :

Bio-based matrix: Poly (lactic acid) (PLA), poly-L-lactide (PLLA),

polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB),

polypropylene (PP), etc.

Natural fibersPlant Animal

Blast Leaf Seed Fruit Stalk WoodWool

FeatherSilk

FlaxHempJute

KenafRattanRamie

SisalManilaCurauaPalm

CottonKapok

CoconutCoir

BambooWheatRice

GrassBarleyCorn

HardwoodSoftwood

7/12Fundamentals of multifunctional composites

• Smart fiber composites

Piezoelectric fiber:Direct piezoelectric effect: the voltage induced by applied force, with applications of sensing, energy harvesting, etc.

Inverse piezoelectric effect: the mechanical strain induced by applied voltage, with applications of noise control, actuation, etc.

Optical fiber:Optical fibers are generally made of extruded glass or plastic,which are good media to transmit light between the two ends of thefiber or strand. Because of this inherent feature, they are widelyused to transmit information over longer distances.

8/12Applications in automotive industry• Current applied techniques

Shape-memory polymers:Airflow control device: shape-memory materials are operate to changeits shape, dimensions, and/or stiffness producing a change in at leastone feature of the airflow control device.

Shape-memory polymer patches: The patch is moulded to the desiredshape of the damaged part and can be activated through heat or light.Once deactivated, it can be attached to the damage surface withadhesives.

Smart fiber composites:Optical fiber: interior lighting system, fiber optic sensor, etc.

Piezoelectric fiber: active vibration suppression, energy harvesting to power wireless autonomous sensors, etc.

9/12Applications in automotive industry• Current applied techniques

Green Composites

Fig. 3. Use of Natural Fibers for Composites in the European Automotive Industry 2012. Source:http://bio-based.eu/news/biocomposites/

10/12Applications in automotive industry• Future potential techniques

Structural supercapacitors of carbon fiber composites

Fig. 4. The concept of multifunctional carbon fiber composites with mechanicalloading and electricity storage features.Source:http://www.compositestoday.com/2013/10/carbon-fibre-could-make-electric-vehicle-batteries-a-thing-of-the-past/

11/12Applications in automotive industry• Future potential techniques

Self-healing composites

Damage is generally an inevitable phenomenon for industryequipment, and much time and labor work have been spent onsuch issues. For future prospect, the vehicle that can repair itselfmight be possible with the development of self-healing materials.

Internal damage: Micro-based method (capsule, vascular,intrinsic) can repair the internal cracks or delaminations throughthe healing agent.External deformation: Once impacted, shape-memory polymerbased structures can be induced to the original shape throughheat or other stimulus.

12/12Conclusions

• Developments of multifunctional composites:– Shape memory polymers– Green composites– Smart fibers: piezoelectric fiber & optical fiber composites– Self-healing composites.

• Applications in automotive industry– Current use: airflow control device, smart sensor, intelligent

lighting systems, etc.– Future potential: structural capacitor, self-healing structures, etc.