The inspection of a Water Friction Brake at Siemens AG/ Berlin was another challenge almost dedicated for this technique. As the specimen consists of several large disks very close to each other, an inspection with a conventional technique only was out of the question. In particular the angle of incidence has to be varied in small steps over a wide range to ensure that the entire volume is penetrated from different directions. For the whole inspection only three phased array probes were re-quired. A standard 16 element longitudinal transducer was used for testing the shaft, and for the inspection of the disks and the area near the shaft two specially designed shear wave probes were applied. Additionally a 70 ° T/R-probe and a 45 °shear -wave probe were used. The control of the probes and the data evaluation was carried out with the Mini-SAPHIR Phased Array Inspection System. This high performance digital instrument, recently designed at the Federal Institute for Materials Research and Testing (BAM)/Berlin and now manufactured by Siemens AG/Erlangen as a licensee, offers the possibility of driving four phased array transducers simultaneously. Thus the inspection could be carried out in a minimum of time without the necessity of time consuming reequipment work. As the device is of small mechanical extensions and easy to set up, not much effort had to be undertaken for the transport and the installation of the system. Data evaluation was carried out with a number of well-tried software tools providing A-scan, TD-scan and echotomography. In particular the presentation of the data in the form of echotomographic images offered an accurate and reliable view into the material. To have a secure control of the probe-coupling and the soundfield parameters, an online TD-scan was displayed on the screen continuously. A self test of the system, monitoring data transmission and environmental parameters like temperature, humidity and the supply voltages, was carried out permanently throughout the inspection. In spite of the complex geometry of the Water Friction Brake, the inspection could be carried out in a remarkably short time. The required sensitivity was even excee-ded. Ob-viously evidence for the effeciency and excellent performance of the Phased Array Technique, which reduces inspection time and costs as well as improving reliability simultaneously. A technique which is commercially available now, as the Mini-SAPHIR a very reasonable and easy-to-operate-system is manufactured by Siemens. |
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G. Schenk BAM VIII.41 Tel.: 030-81043641 Fax: 030-8119396 E-Mail: gottfried.schenk@bam.de | H.-L. Gehr Siemens-KWU Tel.: 09131-18220 Fax: 09131-183948 E-Mail: heinz-ludwig.gehr@erl11.siemens.de |