ENGI 1313 Mechanics I Lecture 35 Analysis of

ENGI 1313 Mechanics I Lecture 35: Analysis of Frames and Machines Shawn Kenny, Ph. D. , P. Eng. Assistant Professor Faculty of Engineering and Applied Science Memorial University of Newfoundland spkenny@engr. mun. ca

Lecture 35 Objective n 2 to illustrate the analysis of frames and machines by example © 2007 S. Kenny, Ph. D. , P. Eng. ENGI 1313 Statics I – Lecture 35

Example 35 -01 n 3 The compound shears are used to cut metal parts. Determine the vertical cutting force exerted on the rod R if a force of F = 20 lb is applied at the grip G. The lobe CDE is in smooth contact with the head of the shear blade at E. © 2007 S. Kenny, Ph. D. , P. Eng. ENGI 1313 Statics I – Lecture 35

Example 35 -01 (cont. ) n Draw FBD Ø GBA Ø CDE Ø FRE F = 20 lb FBC Ax Ay FBC Dy Dx 4 Fy Fx NE © 2007 S. Kenny, Ph. D. , P. Eng. NE ENGI 1313 Statics I – Lecture 35 NR

Example 35 -01 (cont. ) n What FBD and Equilibrium Equations? F = 20 lb FBC Ax Ay FBC Dy Dx Fy Fx NE 5 © 2007 S. Kenny, Ph. D. , P. Eng. NE ENGI 1313 Statics I – Lecture 35 NR

Example 35 -01 (cont. ) n GBA F = 20 lb FBC Ax Ay 6 © 2007 S. Kenny, Ph. D. , P. Eng. ENGI 1313 Statics I – Lecture 35

Example 35 -01 (cont. ) n CDE FBC Dy Dx NE 7 © 2007 S. Kenny, Ph. D. , P. Eng. ENGI 1313 Statics I – Lecture 35

Example 35 -01 (cont. ) n FRE NE Fy Fx NR 8 © 2007 S. Kenny, Ph. D. , P. Eng. ENGI 1313 Statics I – Lecture 35

Example 35 -02 n 9 The kinetic sculpture requires that each of the three pinned beams be in perfect balance at all times during its slow motion. If each member has a uniform weight of 2 lb/ft and length of 3 ft, determine the necessary counterweights W 1, W 2, and W 3 which must be added to the ends of each member to keep the system in balance for any position. Neglect the size of the counterweights. © 2007 S. Kenny, Ph. D. , P. Eng. ENGI 1313 Statics I – Lecture 35

Example 35 -02 (cont. ) n FBD ØA ØB L ØC W 1 Ø Angles? Ay Ay L L W 2 10 By By © 2007 S. Kenny, Ph. D. , P. Eng. Cy ENGI 1313 Statics I – Lecture 35 W 3

Example 35 -02 (cont. ) n Beam A L W 1 Ay 11 © 2007 S. Kenny, Ph. D. , P. Eng. ENGI 1313 Statics I – Lecture 35

Example 35 -02 (cont. ) n Beam B Ay L W 2 12 © 2007 S. Kenny, Ph. D. , P. Eng. By ENGI 1313 Statics I – Lecture 35

Example 35 -02 (cont. ) n Beam C L By Cy 13 © 2007 S. Kenny, Ph. D. , P. Eng. ENGI 1313 Statics I – Lecture 35 W 3

References Hibbeler (2007) n http: //wps. prenhall. com/esm_hibbeler_eng mech_1 n 14 © 2007 S. Kenny, Ph. D. , P. Eng. ENGI 1313 Statics I – Lecture 35