1 / 3

ME 3180 - Mechanical Engineering Design

ME 3180 - Mechanical Engineering Design. Example #1. Example #1. Given:

lawrence-oneal
Download Presentation

ME 3180 - Mechanical Engineering Design

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ME 3180 - Mechanical Engineering Design Example #1

  2. Example #1 • Given: • The pressure vessel lids of nuclear power plants are bolted down to seal the high pressure exerted by the water vapor ( in a boiler reactor) or the pressurized water ( in a pressurized water reactor). The bolts are so heavily stressed that they are replaced after the reactors are opened 25 times. A 20% decrease in stress would give 104 cycles of life. The ultimate strength is 1080MPa. How low does the stress needs to be to give a life of 104 cycles?

  3. Example #1 • Solution: • Type of material was not given; therefore we can’t calculate Marian factors (fatigue modifying factors). • For axial load: S’e = 0.45Sut and Sf at 103 cycles = 0.75Sut • Sf = aNb (eq 7-5) : log(Sf) =log(a) + b.log(N) • Sf = (1350)(104)-0.07395 (eq 7-5) • Sf = 683.2 MPa • The stress need to be decreased to 683.2 MPa to give 104 cycles. eq 7-6

More Related