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2. Principle of the measurement method
Applying an electrical voltage to the piezoelectric element in a transducer causes the piezoelectric material to oscillate, creating sound waves that travel from the transducer, through the liquid or coupling medium and into the screw. This type of ultrasonic wave travels the length of a screw. The acoustic velocity of a material represents the speed at which the wave travels through it. All materials have a representative, or theoretical, acoustic velocity, but the actual acoustic velocity can vary from sample to sample of the same material, and even throughout the material of a particular sample.
It's important to realize that the actual acoustic velocity is not really a constant. It varies between fasteners (screw, stud, bolt) of a similar material, even when the material composition of the fastener is tightly controlled. This...
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Principle of the measurement method
Applications and feedback
Bibliography
Standards and norms
- Fastening elements – Torque/voltage tests – Amendment 1 - NF EN ISO 16047/A1 - 01-13
- Éléments de fixation. Assemblages vissés. Conception, calcul et conditions de montage - FD E 25-030 - 08-84
- Articles de boulonnerie d'usage général. Spécifications techniques. Réception. Commande. Livraison - NF E 27-005 - 10-69
- Éléments de fixation. Essais de fatigue sous charge axiale - NF E 27-009 - 10-69 ...
Patents
US8037772B2. Thread forming fasteners for ultrasonic load measurement and control.
EP787980B1. Measuring a load on a part and monitoring the integrity of the part | Belastungsmessung eines Elementes und Überwachung seiner Integrität | Mesure de la charge dans une pièce et surveillance de l'intégrité de cette pièce.
US5301574A. Hydraulic wrench and piston has rack gear meshed with...
Directory
Manufacturers – Suppliers – Distributors (non-exhaustive list)
• The SKF Group's technical guide to clamping
http://www.skf.com/binary/12-126662/Serrage- hydraulique_10061_FR.pdf
• ULTR A-RS website
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