i have frequencies of bridge that are effected by mass of vehicle. the problem is when any vehicle pass the bridge it would add the its mass to the bridge mass ultimately mass of the bridge will increase. so in general situation the frequency should be decrease when mass will increase but i am getting higher frequencies when vehicle is passing and lower frequencies when vehicle have passed. kindly suggest anything for this problem
thanks
Dear Faran
A researcher is not supposed to know in advance the outcome of his investigations; you need to report your results scientifically based on your assumptions, approach, or precedent investigations. A bridge as the pavement is designed to support cyclic loading (dynamic loading) that generally induce fatigue. The bridge is characterized by its natural frequencies, related to its degree of freedom (DOF). Besides, frequencies produce by cyclic loading of vehicle should be different from the natural frequencies of the bridge to avoid resonance.
Thank you.
Hi Faran,
The mass of the vehicle is not the only parmater here you should also consider the dynamic interaction between the bridge and the passing vehicle! Frequency depends on both stiffness and mass of the system! Stiffness can be varied by the force transfered to the bridge becuase of the motion of the vehicle. If this is an experimental study, you can measure the frequency of the bridge by collecting its acceleration response when the vehicle passess over the bridge, then use FFT of acceleration to find the frequencies of the bridge.
- Badges
- Science topic