nal bearings exhibits stiffness aud, therefore, intlueuces the rigid body and bending critical speeds of the rotor bearing system. In the case of rigid body criticals calculate the cylindrical and conical modes as a function of support spring constant. Then calculate the fluid-film stillness as a function of speed. The intersection of the rotor and bearing chamcteristir!s corresponds to the critical speed. The critical speed of the system may be represented by (14) The design chart given in

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... 15 enables one to calculate directly the critical speed of elastic rotor supported by plain cylindrical joumal bearings. It combines iu one figllI'e the rotor and the bearing data, and the critical speed is found by a trial-and-error process. The left-h and abscissa axis of Fig. 15 is entered with an assumed critical speed It loop is made around the chart. If the loop closes the assumed value was correct, otherwise the process must be repeated with a new critical speed . For example, for LID = 1 FlAW = 2 and ~ k/~ AW = 5 Bv trinl and errOl' , e , 2 C C • J