A Practical Methodology for Assessing the Validity of Strain Gauge Data Obtained from Advanced Composite Structures

1989 ◽  
pp. 835-848
Author(s):  
Stephen R. Hall
Keyword(s):  
Strain Gauge ◽  
Composite Structures ◽  
Advanced Composite ◽  
Gauge Data

Unsteady Flow Analysis and Vibratory Stress Predictions for a High Work Single Stage Turbine Blade

2012 ◽  
Author(s):  
Kurt Weber ◽  
Girish Modgil ◽  
Steve Gegg ◽  
Shyam Neerarambam ◽  
Moujin Zhang
Keyword(s):  
Flow Field ◽  
Strain Gauge ◽  
Flow Analysis ◽  
Forced Response ◽  
Single Stage ◽  
Turbine Stage ◽  
Rotating Blade ◽  
Gauge Data ◽  
Unsteady Flow Analysis ◽  
High Work

The flow field in High-Work Single-Stage (HWSS) turbines differs from traditional turbine flow fields. Operating at increased pressure ratios, wakes and trailing edge shocks at the exit of the vane are more likely to cause a vibratory response in the rotating blade. This flow field can produce increased excitation at harmonics that correspond to the vane passing frequency and harmonics higher than the vane passing frequency. In this paper, blade vibratory stresses in a HWSS gas turbine stage are predicted using unsteady pressures from two Rolls-Royce in-house flow codes that employ different phase lagged unsteady approaches. Hydra uses a harmonic storage approach, and the Vane/Blade Interaction (VBI) code uses a direct storage approach. Harmonic storage reduces memory requirements considerably. The predicted stress for four modes at two engine speeds are presented and are compared with rig test strain gauge data to assess and validate the predictive capability of the codes for forced response. Strain gauge data showed the need to consider harmonics higher than the fundamental vane passing frequency for the max power shaft speed and operating at the conditions. Because of this, it was a good case for validation and for comparing the two codes. Overall, it was found that, stress predictions using the Hydra flow code compare better with data. To the best of the authors’ knowledge, this paper is a first in comparing two different phase lagged unsteady approaches, in the context of forced response, to engine rig data for a High-Work Single Stage turbine.

scholarly journals The development of an advanced composite structure using evolutionary design methods

2009 ◽  
Author(s):  
◽  
David Van Wyk
Keyword(s):  
Composite Materials ◽  
Composite Structure ◽  
Composite Structures ◽  
Empirical Method ◽  
Optimum Shape ◽  
Evolutionary Design ◽  
Structural Optimisation ◽  
Design For Manufacture ◽  
Advanced Composite ◽  
Evolutionary Optimisation

The development of an evolutionary optimisation method and its application to the design of an advanced composite structure is discussed in this study. Composite materials are increasingly being used in various fields, and so optimisation of such structures would be advantageous. From among the various methods available, one particular method, known as Evolutionary Structural Optimisation (ESO), is shown here. ESO is an empirical method, based on the concept of removing and adding material from a structure, in order to create an optimum shape. The objective of the research is to create an ESO method, utilising MSC.Patran/Nastran, to optimise composite structures. The creation of the ESO algorithm is shown, and the results of the development of the ESO algorithm are presented. A tailfin of an aircraft was used as an application example. The aim was to reduce weight and create an optimised design for manufacture. The criterion for the analyses undertaken was stress based. Two models of the tailfin are used to demonstrate the effectiveness of the developed ESO algorithm. The results of this research are presented in the study.

Design and Evaluation of Automated Robotic Ultrasonic Guided Wave Based Inspection System

2017 ◽  
Author(s):  
Scott M. Bland ◽  
Shiv P. Joshi
Keyword(s):  
Composite Structures ◽  
Environmental Changes ◽  
Current System ◽  
Ultrasonic Inspection ◽  
Guided Wave ◽  
Inspection System ◽  
Sensitivity Testing ◽  
Advanced Composite ◽  
Ultrasonic Guided Wave ◽  
Sandwich Materials

This paper discusses the development and testing of an automated robotic ultrasonic guided wave based inspection system developed to provide an efficient, accurate and reliable method for performing nondestructive evaluation and longer term structural health monitoring in advanced composite structures. The development process and challenges in the design of the automated robotic system are described. A number of tests were performed using the developed robotic ultrasonic inspection system on composite honeycomb core sandwich materials. Experiments showed that the developed automated ultrasonic guided wave inspection system was successful at locating disbonds between the core and the facesheets. Environmental sensitivity testing was also performed to characterize the effect of changing temperature and humidity on system performance. These tests indicate that approach was relatively insensitive to environmental changes, so that this approach could be used in service environment without a significant reduction in performance. Current system testing indicates that the described robotic ultrasonic inspection approach offers an accurate and robust method for inspection and long term tracking of advanced structural system health.

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