The support structure of a massive, 110,000 lb, industrial process equipment, subject to random perturbation, is isolated from the vibration of the equipment itself. The isolators used in the random vibration isolation system are made up of low-stiffness springs paired with viscous dampers. Motion control schemes were incorporated into the isolation system to manage […]
Read MoreFluid/structure interaction and the operation of one of the natural gas compressors imparted dynamic forces onto one of the compressed natural gas piping systems of a power plant. The frequency of this dynamic perturbation happened to nearly match the first resonant frequency of the piping system, which in turn resulted in excessive resonant vibration of […]
Read MorePrecision devices such as coordinate measuring machines (CMMs), microscopes, MRI machines, and other test/scanning equipment are highly sensitive to vibration, caused by other nearby equipment or even human activities. The adverse effects of vibration on such devices should be mitigated by properly isolating them from the surrounding via elastically mounting them on their support concrete […]
Read MoreAir mounts, with their attractive attribute of being able to provide the most softness of all mounts of comparable size, have been gaining popularity and widespread use. The drawback of soft mounting is occasional excessive motion of the mounted machine in response to abrupt, impulse-like disturbances (such as starting up or shutting down an engine). […]
Read MoreAn Advanced Mounting System for Diesel Generators Onboard Luxury Watercrafts An ideal mounting system for yacht diesel generators should be ‘soft and highly underdamped’, while the yacht is not moving, i.e., the propulsion engines are off and calm and quiet are expected. This will prevent the transmission of vibration and noise, through the hull, to […]
Read MoreTo lower the vibration transmitted from a 170 KVA diesel generators onboard a super yacht, to the hull (and thus the living quarters) of the boat, it was decided to soft mount that diesel-generator by changing its conventional (elastomeric) mounts to air mounts. The attachment of the exhaust pipe to the engine, as well as […]
Read MorePassive electronic damping using piezoelectric ceramics is a less temperature-sensitive and more tunable alternative to viscoelastic damping treatments. In this damping technique, the mechanical energy of the structure is converted to electrical energy using piezoelectric material. High mechanical stiffness of piezoceramics enables efficient energy transfer to the piezo damper. The electrical energy, in turn, is […]
Read MoreIn four stroke engines, including diesel engines driving generators, each cylinder fires every other revolution. This causes the engine vibration to occur at ½ the engine RPM, called the ½ order vibration, and its higher order harmonics namely 1 order, 1½ order, 2 order. In the case of a diesel generator, in addition to the […]
Read MorePendulum tuned mass dampers (PTMDs) are commonly used in adding damping to tall structures, including high-rise buildings, control and communication towers, stacks, etc. These multi-directional TMDs, which are made up of mass blocks suspended by steel cables or rods, can readily be tuned to the very low natural frequencies associated with the primary modes of […]
Read MoreThe extent of vibration energy that a passive TMD dissipates as well as its effective frequency range (bandwidth) increase with an increase in the mass ratio of the TMD. In addition, the amount of internal damping built into the make-up of a passive TMD increases with the size of that TMD. The TMDs used in […]
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