机械设计-综合方法版p0505.pdfVIP

MACHINEDESIGN-AnIntegratedApproach,4thEd.5-5-1

PROBLEM5-5

Statement:RepeatProblem5-4fortheloadingconditionsofProblem3-5,i.e.,determinethehorizontalforce

thatwillresultontheballfromacceleratinga2000-kgtrailerto60m/secin20sec.Assumea

constantacceleration.FromProblem3-5,thepullforceis6000N.Determinestaticsafetyfactors

for:

(a)Theshankoftheballwhereitjoinstheballbracket.

(b)Bearingfailureintheballbrackethole.

(c)Tearoutfailureintheballbracket.

(d)Tensilefailureinthe19-mmdiameterattachmentholes.

(e)Bendingfailureintheballbracketasacantilever.

Given:a40mmb31mmc70mmd20mm

M100kgF6kNd26mmt19mm

tonguepullsh

S300MPa

y

Assumptions:1.Thenutsarejustsnug-tight(nopre-load),whichistheworstcase.

2.Allreactionswillbeconcentratedloadsratherthandistributedloadsorpressures.

Solution:SeeFigures5-5andMathcadfileP0505.