Problems_II_3 - H ∗ Program II.3.1 ∗ L Apply Clear Names"Global` ∗" DD Off General:spell D Off General:spell1 D H ∗ input data ∗

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Unformatted text preview: H ∗ Program II .3 .1 ∗ L Apply @ Clear, Names @ "Global` ∗ " DD ; Off @ General::spell D ; Off @ General::spell1 D ; H ∗ input data ∗ L d = 1; H ∗ in − major diameter ∗ L p = 0.2; H ∗ in − pitch ∗ L µ = 0.15; M = 60; H ∗ lb − in ∗ L l = 2 p; H ∗ in − lead ∗ L Print @ "Lead l = ", l, " in" D ; dm = d − p ê 2; Print @ "dm = ", dm, " in" D ; λ = ArcTan @ l ê H dm N @ Pi DLD ; Print @ " λ = ", λ ê Degree, " °" D ; θ = ArcTan @ µ D ; Print @ "Friction angle θ = ", θ ê Degree, " °" D ; If @ θ > λ , Print @ "the screw is sef − locking" D , Print @ "the screw is not sef − locking" DD ; H ∗ to the right ∗ L F = M ê H dm ê 2 Tan @ θ − λ DL ; Print @ "Force required to advance screw to the right F = ", F, " lb" D ; H ∗ to the left ∗ L F = M ê H dm ê 2 Tan @ θ + λ DL ; Print @ "Force required to advance screw to the left F = ", F, " lb" D ; Lead l = 0.4 in dm = 0.9 in λ = 8.05226 ° Friction angle θ = 8.53077 ° the screw is sef − locking Force required to advance screw to the right F = 15964.8 lb Force required to advance screw to the left F = 447.742 lb program_II_3_1.nb 1 H ∗ Program II .3 .2 ∗ L Apply @ Clear, Names @ "Global` ∗ " DD ; Off @ General::spell D ; Off @ General::spell1 D ; " −−−−−−−−−−−−−−−− " " input data " " −−−−−−−−−−−−−−−− " " H pitch L mean diameter dm @ mm D " " screw pitch p @ mm D " " coefficient of friction for thread µ " " coefficient of collar friction for thread µ c " " mean collar diameter dc @ mm D " " external load F @ kN D " data = 8 dm → 30, p → 4, µ −> 0.08, µ c −> 0.08, dc → 40, F → 6.4 < " −−−−−−−−−−−−−−−− " "solution" " −−−−−−−−−−−−−−−− " l = 2 p; H ∗ lead ∗ L Ml = 0.5 F dm H π µ dm − l L ê H π dm + µ l L + 0.5 F dc µ c; Print @ "moment to lower load Ml = 0.5 F dm H π µ dm − l LêH π dm + µ l L + 0.5 F dc µ c " D Print @ "Ml = ", Ml ê . data, " @ N m D = ", 10^ H − 3 L Ml ê . data, " @ N m D " D sf = H π µ dm − l L ; "sef − locking condition: H π µ dm − l L > 0 " Print @ " H π µ dm − l L = ", sf ê . data D If @H sf ê . data L > 0, Print @ "the screw is sef − locking" D , Print @ "the screw is not sef − locking" DD Mr = 0.5 F dm H l + π µ dm L ê H π dm − µ l L + 0.5 F dc µ c; H ∗ momemnt to raise the load ∗ L e = F l ê H 2 π Mr L ; Print @ "efficiency e = F l êH 2 π Mr L = ", e ê . data D −−−−−−−−−−−−−−−− input data −−−−−−−−−−−−−−−− H pitch L mean diameter dm @ mm D screw pitch p @ mm D coefficient of friction for thread µ coefficient of collar friction for thread µ c mean collar diameter dc @ mm D external load F @ kN D 8 dm → 30, p → 4, µ → 0.08, µ c → 0.08, dc → 40, F → 6.4 < program_II_3_2.nb 1 −−−−−−−−−−−−−−−− solution −−−−−−−−−−−−−−−−...
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This note was uploaded on 08/29/2011 for the course MECH 3230 taught by Professor Staff during the Spring '08 term at Auburn University.

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Problems_II_3 - H ∗ Program II.3.1 ∗ L Apply Clear Names"Global` ∗" DD Off General:spell D Off General:spell1 D H ∗ input data ∗

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