SAMPE Journal - November/December 2012 - (Page 7)

Feature Article Durability and Reliability of Large Composite Wind Turbine Blades G. Abumeri and F. Abdi Alpha STAR Corporation J. Paquette Sandia National Laboratory Abstract Because of its advantageous weight-to-stiffness and weight-to-strength ratios, the E-glass composite has become more attractive in the design of large wind turbine blade. In this paper, material characterization of E-glass composites was performed to determine the composite’s static and fatigue properties. Also, durability and damage tolerance (D&DT) and fatigue life analyses based on a multi-scale progressive failure analysis (PFA) were performed to determine a large wind turbine blade made of E-glass composites: a) structural integrity, under 140 mph wind pressure, b) improved structural performance, under 140 mph wind pressure and c) fatigue life and the associated damage under 30–60 mph wind pressures. Introduction Recently, the electricity generated by wind power is increasing dramatically. The larger the turbine, the greater the amount of electricity produced. The need of large commercial wind turbine gives rise to challenge in materials and manufacturing technologies. At present, turbine blades are usually made of E-glass fiber reinforced polyester composites. The use of advanced composites in wind blades is becoming more attractive due to its advantageous weight-to-stiffness and weight-tostrength ratios. In addition, composite structures are usually used to subject severe combined environments and are expected to survive for long periods of time. Therefore, it is necessary to assess damage mechanism in large wind blades. Current wind turbine blade design with advanced composites is based on high factors of safety and traditional design/ stress analysis practices to ensure the target static strength levels and service life lengths. To achieve low production costs material systems such as resin-infused woven and stitched fiberglass are utilized to attempt to achieve an approximate $5/ lb pound target product cost. In addition, real-time structural health monitoring is not used to assess the condition of the blades. Finally, the design process can be described as one that focuses on service life rather than damage tolerance. The combination of these design constraints can significantly impact the turbine blade weight and performance. A design process which uses a composite damage modeling approach will lead to blades that are optimized to be damage resistant and tolerant while being light and inexpensive. In this paper, material characterization of E-glass composites is performed to determine the composite’s static and fatigue properties. Also, Durability and Damage Tolerance (D&DT) and fatigue life analyses based on a multi-scale progressive failure analysis (PFA) are performed to determine a large wind turbine blade made of E-glass composites: a) structural integrity, under 140 mph wind pressure, b) improved structural performance, under 140 mph wind pressure and c) fatigue life and the associated damage under 30–60 mph wind pressures. Methodology Durability and Damage Tolerance (D&DT) Analysis Virtual Testing for durability, reliability, risk assessment and constituent material synthesis of a PMC structure is based on an advanced software system, GENOA, which takes full-scale finite element models and breaks down their material properties to the microscopic level. Material properties are updated per computational iteration, reflecting any changes resulting from damage or crack propagation. The hierarchical approach implemented in GENOA (Figure 1) allows integration of a wide range of specialized programs, from micro to macro, into an existing verified progressive failure and probabilistic analysis tool via a plug and play enhancement. This enhancement makes it possible to accomplish synthesis of PMC materials Figure 1. Functionality of GENOA Life Prediction Software1-2. SAMPE Journal, Volume 48, No. 6, November/December 2012 7

Table of Contents for the Digital Edition of SAMPE Journal - November/December 2012

SAMPE Journal - November/December 2012
Contents
President’s Message
Technical Director’s Corner
SAMPE Journal Editorial Calender
Durability and Reliability of Large Composite Wind Turbine Blades
Corporate Partners
Welcome SAMPE’s Newest Members
SAMPE 2013|Long Beach Call for Papers
Materials & Products
SAMPE LinkedIn Communities
SAMPE Upcoming Events
SAMPE Proceedings
Perspectives
Europe News & Views
SAMPE Europe’s SEICO 2013, Paris, France
Polyurethane Composites for Wind Turbine Blades
Industry News
The SAMPE Foundation
Tech Tidbits
Performance Drivers with Glass Fiber Composites for Wind Turbine Blades
SAMPE Tech 2013|Wichita, KS Call for Papers
Advertiser’s Index
Resource Center
SAMPE Membership Application
SAMPE Books & CD’s Order Form
Industry Events Calendar
Statement to Record Ownership

SAMPE Journal - November/December 2012