Overview

Structural verification is of critical importance to design substantiation. Florida Turbine Technologies, Inc. (FTT) offers customers the ability to conduct structural analyses and validate analytical predictions through lab testing. Specific tests offered at FTT's structural test laboratory include the following (click on any link for additional information):

At FTT, material integrity testing can be performed on specimens, components, and assemblies depending on customer requirements and/or hardware availability. Both static and dynamic tests can be performed under combined loading. There is a full complement of instrumentation available to measure temperature, pressure, stress/strain, or deflection under any type of testing. Data acquisition, recording, and analysis are performed using LabVIEW or other industry-recognized systems. Unique test fixtures can be designed and fabricated for individual applications.


Modal Analysis Impact Testing

FTT’s laboratory has the ability to excite multiple modes simultaneously for modal analysis impact testing. Responding modes can be identified through the use of accelerometers, strain gages, or microphones. Frequency response of a component can then be analyzed to determine whether the resonant frequencies are in a critical region of the system operating envelope. Modal analysis can also be used to evaluate numerous components for repeatability or quality control, such as in the case of fundamental bending frequencies for turbine blades. FTT’s lab can also conduct transfer function analysis and mistuning to identify highly responding blades in a bladed-disk configuration.


Holographic Interferometry

Using holographic interferometry, also known as ‘holography’, a component is excited in a low-amplitude vibratory environment while being bathed by coherent laser light administered by one of FTT’s highly trained technicians. Through optics and electronics, the mode shapes and corresponding frequencies of a part can be identified. Holograms are created by extremely small surface deflections resulting from the vibratory excitation, and full field strain measurements can be made. Another application of holography is Non-Destructive Testing.


Low Cycle Fatigue (LCF)/Crack Propagation Testing

Low Cycle Fatigue/Crack Propagation testing, performed at FTT’s laboratory facility, is mainly used for estimation of life for a component. For example, in a gas turbine engine the required LCF life of a component is defined by the number of engine startup cycles or the number of thermal/stress excursions exposed to the part during its full life. FTT’s lab can simulate these thermal or stress cycles in a controlled environment to quantify component or specimen LCF life. FTT offers customers the ability to examine part cracking under a controlled environment to determine the onset of material cracking, and subsequent crack propagation, while monitoring the stresses and corresponding crack orientations and growth rate.


High Cycle Fatigue Testing

High vibratory environments can be extremely demanding on structures, and FTT’s lab can assist the customer in identifying the vibratory capability of a component with High Cycle Fatigue Testing (HCF). HCF tests must be conducted at elevated temperature to account for the material debits at operating temperatures. FTT can design and fabricate a test rig and conduct HCF testing on a variety of specimens or components, and under a variety of environmental conditions.


High Frequency and Low Frequency Vibratory Excitation

FTT’s structures test laboratory is capable of exciting components under a range of frequencies. Electrodynamic vibration shakers are available to excite parts at low frequencies, from one hertz to several thousand hertz. Piezoelectric shakers can excite parts at frequencies up to 30,000 hertz. Structures test labs are typically limited in the ability to produce this high frequency excitation, but FTT offers customers state-of-the-art test equipment and expertise with dynamic fatigue testing. Strain gage and stress ratio data can easily be generated on components at room temperature or up to 2000 degrees Fahrenheit, under high frequency or low frequency test conditions.


Wear Testing

FTT’s laboratory can evaluate wear coatings or measure coefficients of friction of components to ascertain rub or wear characteristics. Test rigs can be designed to impart relative motion on adjacent components to assess wear coating effectiveness and cyclic life expectancy.


Static Load Testing

FTT’s laboratory can determine buckling loads, limit or ultimate loads, or creep on parts at room temperature or elevated temperature. Load cells are used to apply forces to components under simulated operating conditions, and results are used to validate designs and analyses.


Failure Analysis

FTT’s structures test laboratory has the capability of analyzing and reproducing part failures in a controlled environment to assist customers in understanding the cause of the failure. FTT lab personnel are experienced in evaluating field components. They can identify incipient failures such as wear or crack initiation as well as more severe distress on a piece of hardware. A commonly used lab test method is to reconstruct part failure in a manner that directly replicates the actual operating conditions and the part limitations or failure mechanisms can be well documented and understood.


Damping

FTT's technical team can offer customers damper design and laboratory verification testing. In high vibratory environments, components often require dampers to reduce their amount of motion and limit dynamic response under loading. Mechanical dampers such as turbine blade platform dampers or viscoelastic/friction coatings can be tested to determine their effectiveness in specific applications.


Stress Pattern Analysis by Thermal Emission (SPATE)

FTT's SPATE system provides a full-field non-contacting imaging system that is used to characterize the behavior of materials and structures under stressed conditions. By illuminating a component with laser light while undergoing low-amplitude vibratory excitation, highly stressed regions can be precisely identified. Real-time images of variations in thermoelasticity can be recorded to a resolution of 0.001 degrees Celsius. A visual image is generated which provides a correlation between stress and dynamic loading.