Logo: University of Southern California

Project Title:

Ageing and Fatigue of Glass Fiber Reinforced Polymers

 

Student Researcher(s):

Yinghui Hu, Ph.D. student

Xiaochen Li, Master student

Augustus Lang, Undergraduate student

 

Summary:

Today’s global wind energy industry is growing fast (20% per year). Many wind energy plants are built on the seashore because of the high wind energy level. The wind turbine blades are generally made of composite laminates because they are lighter than metals thus can provide more energy. Although the energy efficiency is high for composite materials, the ageing and fatigue property under wind loads, seawater corrosion and moisture ageing is unknown and needs to be studied. Two composite systems are studied: epoxy with glass fibers and polydicyclopentadiene (pDCPD) with glass fibers. Both are aged in pure water and salt water at elevated temperatures and fatigue properties are studied at different ageing times. The neat resin fracture toughness after ageing is also studied to correlate the resin property with composites property. The glass transition temperature, static tensile property, short beam shear (SBS) strength are also monitored during the ageing process.

The oxidation and creep properties of the new type of pDCPD resin are investigated for long term durability. For oxidation research, bulk sample is oxidized and nano-indentation is used to study the oxidation layer evolution. Thin-film sample is oxidized for Fourier transform infrared spectroscopy (FTIR) analysis to study the chemical change of the resin. For creep research, short-term thin-film tensile creep test is conducted using dynamic mechanical analysis (DMA) while long-term creep is studied using special-designed load frames.

 

 

Wind turbine on the seashore

 

Fatigue failure of 0 degree laminates after ageing 
 

Fracture surface of 90 degree laminates