Reliable determination of natural frequencies and vibration behavior is a key task in the development and quality assurance of turbine, compressor and engine blades. Especially in aerospace, accurate insight into—and reproducible measurement of—dynamic properties is critical for component safety, service life and release processes. For users, this means robust test results, traceable assessments, and a reliable basis for making development, release and quality decisions with confidence.
With the Turbine and compressor blade teststand | TBT, MAUL-THEET offers a solution designed precisely for these requirements: a structured and flexible platform for experimentally determining resonance frequencies under real clamping conditions while maintaining a high level of reproducibility of the test conditions. This enables users to achieve comparable measurement results, robust evaluations and efficiently structured test workflows.
From individual measurements to a systematic test strategy
The TBT is designed to characterize different blade types efficiently. Depending on the application, various excitation methods as well as sensors for pressure and temperature measurement are available, allowing the test setup and data acquisition to be tailored specifically to the respective test task. This increases flexibility in day-to-day testing and supports cost-effective execution of different measurement tasks on a single platform.
Vibration excitation is typically performed by impact excitation using a modal hammer, stimulating a broadband frequency spectrum. Combined with suitable sensors—such as laser Doppler vibrometers, microphones or accelerometers—the dynamic properties of the blades can be captured in a targeted and non-destructive (NDT) manner.
The system enables measurements in frequency ranges up to 40kHz with a frequency resolution of <1Hz at 20kHz, allowing even subtle structural-dynamic effects to be detected reliably. For users, this means precise identification of relevant resonances and thus a robust basis for assessment, optimization and release.
Reproducibility starts with the clamping setup
A key factor in blade testing is the clamping. It directly influences the vibration behavior and must therefore be set in a controlled and reproducible manner.
The TBT addresses this point directly through its integrated hydraulic solution. Clamping forces are recorded, visualized and monitored—measurements outside the permissible range are blocked by the system. This reduces the risk of invalid test results, increases comparability between measurements and supports consistent process quality.
Depending on the requirements, different configurations are available:
- Integration into customer-specific clamping systems,
- manual hydraulic solutions for flexible applications,
- as well as PLC-controlled hydraulic systems for automated and stable test processes.
In particular, the PLC-controlled variant enables precise control of the clamping forces and keeps them stable even over measurement times of up to 30min—an important factor especially for modal analyses. Clamping forces of up to 650kN are provided for controlled operation. This gives users higher reproducibility, reduced operator influence and robust test conditions even for demanding measurement tasks.
Turning measurement data into robust results
Evaluation is carried out using the TBT software, which was developed specifically for the requirements of blade testing. It supports users in analysing measurement data efficiently, interpreting results consistently, and documenting test decisions in a traceable manner. Among other things, it offers:
- Display of time-domain and frequency-domain signals,
- Analysis of FFT and spectral data,
- as well as functions for determining transfer functions and coherence.
Optimized peak-picking algorithms are used to identify resonances, delivering reliable results even with noisy measurement signals. This increases evaluation reliability and reduces the need for manual post-processing.
In addition, the integrated temperature compensation enables correction of temperature-related frequency shifts. This improves comparability of measurement results and allows temperature effects to be taken into account specifically during evaluation.
The software also supports structured data management, work order organization and automated report generation. This reduces administrative effort, improves traceability and makes it easier to integrate the testing process into existing development and quality assurance workflows.
Referencing using master blades
A key element of structured blade testing processes is the use of master blades. They serve as a reference for evaluating production parts and enable consistent interpretation of measurement results across different batches and over time.
The TBT software supports this approach through integrated management of master blades and reference data in a blade database. This allows deviations in vibration behavior to be recorded and evaluated systematically—for example with regard to manufacturing tolerances, material variability or process changes. Users thus gain a robust basis for identifying deviations at an early stage and assessing them in a well-founded manner.
Especially in safety- and quality-critical applications—such as aerospace and the gas and steam turbine sector—where traceability and clearly defined acceptance criteria are essential, referencing against master blades provides a robust, auditable basis for evaluation. Measurement results are not considered in isolation; they are assessed against a defined reference, making them comparable in a traceable manner.
Especially in industrial environments with increasing production volumes, this approach provides the basis for consistent test decisions, stable quality assurance, and a clear framework for release decisions or deviation assessments.
Flexibility for different testing requirements
A key feature of the TBT is its adaptability. The setup and configuration can be tailored specifically to customer requirements—from straightforward measurement tasks to automated testing workflows in series production environments. This allows the test stand to be adapted to existing processes as well as to growing requirements, without having to implement a dedicated solution for every test task.
This makes the test stand suitable for:
- Research and development environments,
- Validation and verification processes,
- as well as for production-representative testing in quality assurance.
Technology for today’s industrial requirements
The TBT is a proven product designed to meet the current requirements of an evolving industry: rising production volumes, higher demands for traceability, and the need for robust, reproducible measurement processes. For users, this means greater process reliability, better comparability of measurement results, and a solid basis for decisions in development, quality assurance and production.
The test stand combines proven measurement principles with a clear system architecture and modular expansion options. This results in a solution that can be integrated into existing processes, can scale with new requirements, and provides a reliable basis for structured testing and release decisions.
With the Turbine and compressor blade test stand | TBT, you create the basis for reproducible measurement results, stable and non-destructive testing processes, and traceable release decisions. Talk to us about how the test stand can be adapted to your requirements and processes.
