Sökning: "small amplitude excitation"

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden small amplitude excitation.

1. 1. Vibrational energy harvesting for sensors in vehicles

   Författare :Johan Bjurström; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; piezoelectric; anti-resonance; electromagnetic induction; prescribed displacement; low frequency; nonlinear dynamics; small amplitude excitation; automotive safety; vibration energy harvesting; unified modeling;

   Sammanfattning : The miniaturization of semiconductor technology and reduction in power requirements have begun to enable wireless self-sufficient devices, powered by ambient energy. To date the primary application lies in generating and transmitting sensory data. LÄS MER

3. 2. Rail Corrugation Growth on Curves

   Författare :Peter Torstensson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; short-pitch rail corrugation; rotating flexible wheelset model; small radius curves; prediction of long-term roughness growth; plastic deformation; non-Hertzian and non-steady wheel‒rail contact; wear; rutting corrugation;

   Sammanfattning : The development of periodic irregularities with distinct wavelengths (corrugation) on the low rail of small radius curves is studied through mathematical modelling, numerical simulations, field measurements and laboratory investigations. One year of monitoring of roughness on the low rail of a 120 m radius curve on the metro of Stockholm Public Transport (SL) showed severe growth of rail corrugation with wavelengths of about 5 cm and 8 cm. LÄS MER

4. 3. Modeling of losses in power transformers from dc to the low kilohertz range

   Författare :Julius Krah; Göran Engdahl; Roland Eriksson; Anthony Moses; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical power technology; power transformer; losses; magnetic hysteresis; magnetic measurement systems; medium frequency; eddy currents; skin effect; thermal diffusion; Elkraftteknik; Electric power engineering; Elkraftteknik;

   Sammanfattning : The development of HVDC converters, local generation and tractions systems increases the demand for power converters. While a lot of studies have been conducted on the power electronics, there are still open questions concerning the contained power transformer that operates at a few kilohertz. LÄS MER

5. 4. Low-cost control of discontinuous systems including impacts and friction

   Författare :Fredrik Svahn; Annika Stensson Trigell; Harry Dankowicz; Jenny Jerrelind; Remco Leine; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinear dynamics; discontinuities; nonlinear control; impacts; friction; vehicle suspensions; Vehicle engineering; Farkostteknik;

   Sammanfattning : For a successful design of an engineering system it is essential to pay careful attention to its dynamic response. This is particularly true, in the case of nonlinear systems, since they can exhibit very complex dynamic behaviour, including multiple co-existing stable solutions and chaotic motions, characterized by large sensitivity to initial conditions. LÄS MER

7. 5. On Nonlinear Acoustics in Contrast Echocardiography

   Författare :Marcus Ressner; Birgitta Janerot-Sjöberg; Per Ask; Tomas Jansson; Hans Torp; Linköpings universitet; []
   Nyckelord :TECHNOLOGY; TEKNIKVETENSKAP;

   Sammanfattning : Ultrasound is one of the most commonly used noninvasive medical imaging techniques. Ultrasound contrast agents (UCA), consisting of encapsulated gas-filled microbubbles, have shown to increase the diagnostic precision in selected low echogenic patients. LÄS MER