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Showing result 1 - 5 of 17 swedish dissertations matching the above criteria.

  2. 1. Piezoelectric Generation and Damping of Extensional Waves in Bars

    Author : Anders Jansson; Bengt Lundberg; Urmas Valdek; Peter Olsson; Uppsala universitet; []
    Keywords : Technology; Piezoelectric; wave; generation; damping; bar; TEKNIKVETENSKAP;

    Abstract : This thesis focuses on the electromechanical processes of generation and damping of transient waves in bars with attached piezoelectric members. In particular, the influence of amplifier and electrical circuitry on the mechanical waves is of interest. READ MORE

  4. 2. Detecting Inclusions in a Silicone Rubber Phantom Using Standing Lamb Waves and Multiple Frequency Footprints

    Author : Ulf G Jonsson; Britt Andersson; Olof A Lindahl; Jacques Ohayon; Umeå universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Piezoelectric; Silicone rubber; Impedance; Resonance; Lamb waves; Phantom; Electronics; elektronik;

    Abstract : The thesis deals with one major question: is it possible, using one piezoelectric sensor/vibrator, to detect a hard inclusion in a silicone rubber phantom? The question was approached with an open mind and the task was subdivided into three clearly identifiable parts: characterization of the piezoelectric sensor/vibrator (paper I), creating a model of the visco-elastic properties of a tissue-like material (phantom) in contact with the sensor/vibrator (paper II), and to detect the presence of a hard inclusion in the phantom (paper III). All vibrations of the sensor/vibrator and phantom was modeled using a finite element method (FEM). READ MORE

  5. 3. Active Health Monitoring of Aerospace Composite Structures by Embedded Piezoceramic Transducers

    Author : Christophe Paget; KTH; []
    Keywords : embedded; piezoceramic; piezoelectric; transducer; composite; structural; integrity; health monitoring; damage detection; Lamb waves; wavelets; normal-mode expansion; FE-method; SLMT;

    Abstract : The objectives of the thesis work were to study theinteraction between embedded piezoceramic transducers andcomposite structures as well as determine techniques tosimplify the Lamb waves analysis. Firstly, this studyconsidered the design of the embedded piezoceramic transducers. READ MORE

  6. 4. Active Junction Control and Piezoelectric Hybrid Damping for Improving the Acoustic Performance of Lightweight Structures

    Author : Jonas Svensson; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hybrid passive-active control; Piezoelectric shunt damping; Sound radiation; Active junction control;

    Abstract : Weight reduction is a key factor in lowering the fuel consumption and thereby the greenhouse emissions from vehicles. However, reducing the weight normally results in a deterioration of the acoustic performance. Thus, the purpose of this thesis is to investigate damping treatments for lightweight vehicle panels. READ MORE

  7. 5. Elastic Stability and Piezoelectric Power Generation Using ZnO Nanostructures

    Author : Riaz Mohammad; Magnus Willander; Omer Nour; Shunri Oda; Linköpings universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP;

    Abstract : Nanotechnology combines the effort between science and engineering using the approaches of either top-to-bottom or bottom-to-top techniques. A hybrid approach of the above techniques is also used for the fabrication of nanodevices. READ MORE