Design Audits.

Tutorialpg. 153-168Dynamic design audits of machinery can identify potential problems before the machine is manufactured, thus preventing costly project delays and downtime. The types of audits that should be performed are discussed and typical analysis results are presented along with guidelines as to their interpretation

Analysis Of Torsional Vibrations In Rotating Machinery.

Tutorialpg. 127-15

Piping Vibration Analysis.

Tutorialpg. 119-134Excessive piping vibrations are a major cause of machinery downtime, leaks, fatigue failures, high noise, fires, and explosions in refineries and petrochemical plants. Excessive vibration levels usually occur when a mechanical natural frequency of the piping system is excited by some pulsation or mechanical source. The vibration mode shapes usually involve lateral vibrations and/or shell wall radial vibrations. Simplified methods are presented for analyzing lateral and shell wall piping vibrations and judging their severity. The methods are thought to be conservative and are intended to be used as screening criteria to determine if more sophisticated analyses, such as computer stress modelling or strain gage testing are necessary. Frequency factors for calculating the mechanical natural frequencies for the classical piping configurations (uniform straight beams) and various piping bend configurations are presented. Factors are presented to compensate the natural frequency calculations for concentrated and distributed weight effects. The relationships between piping vibration displacement, velocity and stress are presented and criteria for judging the severity of piping vibration in terms of the endurance stress limit are shown. The mechanisms that can excite piping vibrations will be discussed, as well as methods for controlling their severity

Critical Speed Analysis Of An Eight-Stage Centrifugal Pump

Lecturepg. 59A critical speed and unbalance response analysis of an eight-stage centrifugal pump was performed, considering the variation of stiffness and damping coefficients with speed for both the oil firm bearings and the fluid seals (interstage, neck ring and balance position). The rotor response to unbalance was predicted and compared to measured test stand data, utilizing four different methods to estimate he fluid seal effects. The comparison showed that correlation was best when using the latest finite length seal procedures. The wide variation in predicted critical speeds and response amplitudes indicates the need for additional research in this area, to define the exact stiffness and damping values for fluid film seals