(20 min.) Case Study: Bounty Hunt for Natural Frequencies on the Natural Gas Pipe Lines: Analysis & Counter measures

Özgün Yakar, Head of Technical Department, Prüftechnik Turkey


The presentation provides information related to a case study which is about the high vibration levels on a natural gas pipe lines and how are they reduced dramatically. Natural gas pipe lines at a compressor station suffer from high vibration levels and because of that the compressors cannot be loaded properly. The vibration measurements have been collected from equally spaced measurement points along the long piping and then analyzed. The symptoms were showing that the piping is under the effect of powerful resonances which is excited by the natural gas turbulent flow. The vibration levels have been compared with VDI 3842 guideline and this also showed that the limits specified by the guideline has been exceeded. To be sure about the “resonance” diagnosis, it is decided to perform modal test on the piping. FRF graphs confirmed that the first three bending modes of the piping structure were responsible of the high vibration levels. An analysis has been performed on the modal test software and the mode shapes of the first three modes have been visualized. An engineering estimation/optimisation has been done on the mode shape simulations and a clamping points has been determined. Vibration clamps has been used as a damping element to reducing vibration levels. Vibration levels extremely reduced after installation of the vibration clamps. Many illustrations of mode shapes are included in the presentation.


1. Understand pipe vibrations
2. Understand modal testing
3. Reducing resonance vibrations with vibration clamps


The author is born in İzmir-Turkey in 30.12.1986. He graduated from the Mechanical Engineering Department of Dokuz Eylül University in İzmir. He continued his academical studies in Istanbul Technical University under the Machine Dynamics, Vibration and Acoustics Programme. At the same time he worked in Marmatek Engineering the distributor of Prüftechnik in Turkey. With two years of experience on-site as a vibration analyst, he joined the Noise-Vibration and Harshness department of the Ford Otosan as a product development engineer. He was responsible of the vehicle air induction system acoustical quality. He gained extensive knowledge about the acoustics and experience about the on-site testing. He joined Prüftechnik Turkey team as head of technical department after three and a half years of experience in Ford. With the support of the theoretical knowledge he gained at the technical university while he was performing his PhD and hands-on experience obtained in the professional testing career, he is using the scientific approach to the solve the vibration problems during his daily work.