Sökning: "impact-echo"

Hittade 4 avhandlingar innehållade ordet impact-echo.

  1. 1. MODELLING AND SIMULATION OF ELASTIC & PLASTIC BEHAVIOUR OF PROPAGATING IMPACT WAVE : Impact- echo and Explosive welding process development

    Författare :Mohammad Tabatabaee Ghomi; Jafar Mahmoudi; Golamhoosin Liaghat; Hamid Bahai; Mälardalens högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Energy- and Environmental Engineering; energi- och miljöteknik;

    Sammanfattning : A force that is applied dynamically in a short period of time is called an impact force (shock wave). Due to the concentrated application of force on a small area in a fraction of a second, unique applications have emerged that other types of loadings are not capable of performing. LÄS MER

  3. 2. Lamb wave evaluation of concrete plates

    Författare :Oskar Tofeldt; Teknisk geologi; []
    Nyckelord :Lamb waves; guided waves; impact-echo; concrete; non-destructive evaluation;

    Sammanfattning : This thesis is about the application of Lamb waves for non-destructive evaluation of plate-like concrete structures under one-sided access test condition using a portable equipment consisting of an accelerometer and impact hammer. With this type of equipment and based on array signal processing, the impact-echo (IE) method can be extended with measurements of surface waves; this extension allows an evaluation with Lamb waves. LÄS MER

  4. 3. Air-coupled microphone measurements of guided waves in concrete plates

    Författare :Henrik Bjurström; Nils Rydén; Björn Birgisson; Tadeusz Stepinski; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Non-destructive testing; Lamb waves; surface waves; air-coupled microphones; non-contact measurements;

    Sammanfattning : Quality control and quality assurance of pavements is today primarily based on core samples. Air void content and pavement thickness are parameters that are evaluated. However, no parameter connected to the stiffness is evaluated. LÄS MER

  5. 4. Non-contact surface wave measurements on pavements

    Författare :Henrik Bjurström; Nils Rydén; Björn Birgisson; Jinying Zhu; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; seismic testing; asphalt concrete; dynamic modulus; non-contact measurements; rolling measurements; surface waves; Lamb waves; MEMS microphones; Byggvetenskap; Civil and Architectural Engineering;

    Sammanfattning : In this thesis, nondestructive surface wave measurements are presented for characterization of dynamic modulus and layer thickness on different pavements and cement concrete slabs. Air-coupled microphones enable rapid data acquisition without physical contact with the pavement surface. LÄS MER