The term torsional critical speed of centrifugal pumps and associated drive equipment refers to the speed of a pump rotor or related rotating system that corresponds to a resonant frequency of torsional vibration of the rotating system. Torsional critical speeds are associated with torsional or angular deflection of the rotor and are not to be confused with lateral critical speeds associated with lateral deflection. The two are separate entities. A given rotor or rotating system may possess more than one torsional resonant frequency or torsional critical speed. The lowest frequency which produces the "first mode shape" and "first torsional critical speed" is in general of the most concern. Torsional vibration is caused by torsional excitation from sources such as variable frequency drive motor toque pulsations, combustion engine torque spikes and impeller vane pass pulsation. The calculation of the first torsional critical speed is fairly simple for simple rotor systems.
in torsional vibrations moment of inertia is a very important determining factor. it is a quantitative measure of the resistance of an object to torsion. it is synonymous to mass in displacement systems. the greater the moment of inertia the lesser the degree of torsional vibrations and vice versa. moment of inertia relates torsional vibrations to the geometry of the part considered irrespective of its composing material and its strength.
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Power output will increase. Beyond the critical speed, torsional failure may occur.
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John C. Houbolt has written: 'Coupled bending and torsional deformations of twisted rotating blades under arbitrary loading'
Torsional analysis: This analysis completed based on strcture properties like Mass MI and Torsional stiffness. Torsional critical speed analysis: Speed of rotor will come into picture in addition to Mass MI and Torsional stiffness of the structure.
Hardness in torsion refers to the resistance a material has to deformation when subjected to torsional (twisting) forces. It is a measure of the material's ability to withstand twisting without undergoing plastic deformation. Hardness in torsion is important in applications where components are subject to torsional loading, as it indicates the material's resistance to structural failure under twisting forces.
It is defined as ratio of the product of modulus of rigidity and polar moment of inertia to the length of the shaft. Torsional Rigidity is caluclated as: Torsional Rigidity= C J/l
The term torsional critical speed of centrifugal pumps and associated drive equipment refers to the speed of a pump rotor or related rotating system that corresponds to a resonant frequency of torsional vibration of the rotating system. Torsional critical speeds are associated with torsional or angular deflection of the rotor and are not to be confused with lateral critical speeds associated with lateral deflection. The two are separate entities. A given rotor or rotating system may possess more than one torsional resonant frequency or torsional critical speed. The lowest frequency which produces the "first mode shape" and "first torsional critical speed" is in general of the most concern. Torsional vibration is caused by torsional excitation from sources such as variable frequency drive motor toque pulsations, combustion engine torque spikes and impeller vane pass pulsation. The calculation of the first torsional critical speed is fairly simple for simple rotor systems.
a colloquialism
The torsional stress refers to the stress that arises from the deformation set up by a twisting moment or torque.
Torsional rigidity of a shaft, also known as torsional stiffness, refers to the shaft's resistance to twisting under an applied torque. It is a measure of how much the shaft twists relative to the applied torque. Torsional rigidity is important in applications where precise torque transmission is required without excessive twisting or deformation of the shaft.
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The speed of a torsional wave depends on the material it is propagating through. In general, torsional waves travel slower than longitudinal waves in the same material. The speed can be calculated using the material properties like shear modulus and density.
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in torsional vibrations moment of inertia is a very important determining factor. it is a quantitative measure of the resistance of an object to torsion. it is synonymous to mass in displacement systems. the greater the moment of inertia the lesser the degree of torsional vibrations and vice versa. moment of inertia relates torsional vibrations to the geometry of the part considered irrespective of its composing material and its strength.