STRENGTH TESTING AN EMBEDDED SENSOR BLADE BOLT FOR WIND TURBINE APPLICATIONS

Authors

Scott Larwood, University of the PacificFollow

Introduction/Abstract

The LORD Corporation, MicroStrain Sensing Systems has developed a blade bolt with embedded load sensor (Bolt-Link) for wireless load measurement and control. The Bolt-Link was strength tested to examine its potential use for wind turbine applications.

Purpose

Confirm structural integrity and sensor reliability of the Bolt-Link by applying test loads that represent the ultimate and fatigue bolt loads for a typical 1.5 MW wind turbine (20 year life).

Method

Ultimate loads are same as standard bolt

Fatigue loads (20 year life) determined from 1.5 MW turbine model and modified to a single load applied one-million times

Calibrate sensor to the limit of the test machine (50,000 lb = 50 kip)

Design/build lever system to double load capacity (100 kip)

Test six Bolt-Links to maximum load failure

Test six Bolt-Links (two instrumented) in fatigue to one-million cycles, continue and stop at two-million cycles (two lifetimes)

Results

Evidence of bolt bending during ultimate load testing

Range of ultimate loads from 97 kip to 102 kip (criteria 99.3 kip)

Six bolts tested to two-lifetimes with no failures

Two bolts with sensors tested to two-lifetimes with no sensor failures

Significance

Test results confirm the structural integrity and sensor reliability within a wind turbine application

Cannot determine true ultimate load due to bending from lever system; however, Bolt-Link expected to meet ultimate load criteria

Bolt-Link should be tested in a complete blade fatigue test for further verification

Location

DeRosa University Center, Stockton campus, University of the Pacific

Format

Poster Presentation