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Bachelor's Thesis
Author of thesis: Václav Kovář
Acad. year: 2025/2026
Supervisor: Ing. Vladimír Skřivánek
Reviewer: Ing. Petr Lošák, Ph.D.
Vibrations are among the leading causes of fatigue and failure in mechanical structures, with modal hammers being commonly used for experimental determination of dynamic properties. However, manual excitation suffers from limited repeatability and the risk of double hits. The aim of this thesis was to design and build an automated mechanism for impact excitation using a commercial PCB 086C03 modal hammer to eliminate these shortcomings. Existing approaches to impact excitation automation were reviewed and compared. Based on this comparison, a rotating hammer principle with a cam mechanism driven by two DC motors and a servo-controlled catch system was selected. The device was integrated into a compact 3D-printed module mounted on a photographic tripod with a control system based on the ESP32 platform. The prototype was validated by experimental measurements on two aluminium beams successfully identifying two eigenmodes. The results confirmed reliable impact force repeatability. A rubber tip is recommended for thin compliant structures, as it eliminates the risk of double hits. However, for universal use independent of the stiffness of the measured structure, the catching mechanism would need to be modified.
impact excitation automation, modal hammer, cam mechanism, ESP32, 3D printing, experimental dynamics
Date of defence
10.06.2026
Result of the defence
Defended (thesis was successfully defended)
Grading
C
Process of defence
Při obhajobě student nejprve prezentoval svoji bakalářskou práci, následně byly přečteny posudky a student odpovídal na dotazy oponenta. Poté byly členy komise položeny následující otázky: Popište člen x v uvedeném vztahu pro výpočet směrodatné odchylky. Proč byl pro implementaci vybrán IR senzor, má použití IR nějaký význam? Co je příčinou vzniku dvojitých rázů? Poznámka k realizaci zdvihnutí kladívka s cílem předejít dvojitému rázu. Na závěr byla obhajoba hodnocena jako dobrá.
Language of thesis
Czech
Faculty
Fakulta strojního inženýrství
Department
Institute of Solid Mechanics, Mechatronics and Biomechanics
Study programme
Mechatronics (B-MET-P)
Composition of Committee
Ing. Martin Appel, Ph.D. (místopředseda) doc. Ing. Radek Vlach, Ph.D. (člen) Ing. Jan Pokorný, Ph.D. (člen) Ing. Lubomír Houfek, Ph.D. (člen) Ing. David Vlachý (člen) Ing. Michal Bastl, Ph.D. (člen) Ing. Stanislav Frolík, Ph.D. (člen) Pplk. Ing. Radek Doskočil, Ph.D. (předseda)
Supervisor’s reportIng. Vladimír Skřivánek
Grade proposed by supervisor: B
Reviewer’s reportIng. Petr Lošák, Ph.D.
Grade proposed by reviewer: C
Responsibility: Mgr. et Mgr. Hana Odstrčilová