EE 245: Introduction to MEMSLecture 15: StressGradientsCTN 10/19/09Copyright © 2009 Regents of the University of California• Announcements:• Lecture schedule for the next 4 weeks:• Midterm Exam:ª Tu, Nov. 3, during regular lectureª 1.5 hours, but might go longerMonday Tuesday Wednesday Thursday FridayOct. 5Lecture5-6:30241 Cory6Lecture3:30-5Moffitt7 8Discuss3:30-5Moffitt912Lecture5-6:30241 Cory13 14 15Discuss3:30-5Moffitt1619Lecture5-6:30241 Cory20Lecture3:30-5Moffitt21 22Lecture3:30-5Moffitt2326Discuss3:30-5Moffitt27 2829Lecture3:30-5Moffitt30Nov. 2Lecture5-6:30241 Cory3Midterm3:30-5Moffitt45Lecture3:30-5Moffitt6• Today:• Reading: Senturia, Chpt. 9• Lecture Topics:ª Bending of beamsª Cantilever beam under small deflectionsª Combining cantilevers in series and parallelª Folded suspensionsª Design implications of residual stress and stress gradients• ----------------------------------Problem: Bending a Cantilever Beam•Objective: Find relation between tip deflection y(x=Lc) and applied load F•Assumptions:1. Tip deflection is small compared with beam length2. Plane sections (normal to beam’s axis) remain plane and normal during bending, i.e., “pure bending”3. Shear stresses are negligibleFx′LcxClamped end condition:At x=0:y=0dy/dx = 0Free end conditionEE 245: Introduction to MEMSLecture 15: StressGradientsCTN 10/19/09Copyright © 2009 Regents of the University of CaliforniaEE 245: Introduction to MEMSLecture 15: StressGradientsCTN 10/19/09Copyright © 2009 Regents of the University of CaliforniaFx′LcxClamped end condition:At x=0:y=0dy/dx = 0Free end conditionEE 245: Introduction to MEMSLecture 15: StressGradientsCTN 10/19/09Copyright © 2009 Regents of the University of CaliforniaEE 245: Introduction to MEMSLecture 15: StressGradientsCTN 10/19/09Copyright © 2009 Regents of the University of
View Full Document
Unlocking...