0 Engineeing Mechanics - Statics 0 Engineeing Mechanics Statics Cuse Web site: www.pages.dexel.edu/~cac54 COUSE DESCIPTION This cuse cves intemediate static mechanics, an extensin f the fundamental cncepts and methds f static mechanics intduced in the feshmen cuse tdec, and tdec 3. Tpics include pblem fmulatin and slutin methds; tw- and thee-dimensinal vect epesentatins f fces, mments, and cuples; static equilibium f paticles, igid bdies, and engineeing stuctues; analysis f extenal and intenal fces in stuctues via the methds f fee-bdy diagams; and ppeties f css-sectinal aeas. PEEQUISITE(S) Sphme standing; tdec, tdec 3. Lectues ae based n the textbk Engineeing Mechanics STATICS, nd ed., by William. iley and Ley D. Stuges, Jhn Wiley & Sns, Inc. 996.
0 Engineeing Mechanics - Statics COUSE OBJECTIVES This cuse is aimed at pviding the stating engineeing students in thei sphme yea a smth tansitin fm science-based mechanics pblems t engineeing-based mechanics pblems, i.e. fm equilibium f elatively simple fce systems t fce systems in stuctues with cnnected membes and with cmplex gemety. Cnduct f the cuse emphasizes the cect and efficient fee-bdy epesentatin f the membes in the stuctual system, alng with fmatted but lgical slutin techniques f the pblems. The specific cuse bjectives ae: Efficient use f tignmetic functins t decmpse fces in selected cdinate diectins; Pficiency in cmputing mments by fces abut a selected pint; Cnfidence in epesenting cectly a fee-bdy diagam f a membe in a laded stuctue; Cnfidence in setting up and the slutin t the fee-bdy diagam n hand; Undestand the physical natue f the intenal fce and mments in a stuctual membe; Cnfidence in handling the ppeties f a given css-sectinal aea f any shape; amilia with the unique chaacteistics f tensin, cmpessin, sheaing, bending, and tsin in stuctual membes.
0 Engineeing Mechanics - Statics COUSE EQUIEMENTS Class attendance (CA): Class attendance is mandaty, and is cunted as 0% f yu final tem gade. A sign-up sheet will be ciculated duing each lectue and ecitatin t ecd the attendance. Please infm instuct/ta pi t the lectue/ecitatin that yu can nt attend. Hmewk assignments (HW): HW assignments and thei due dates ae listed in Cuse Outline. HW will be cllected, ecded, but nt checked. A gade will be given t each HW based n numbe f pblems that have been cmpleted and submitted. HW gade f the entie tem will be cunted as 0% f yu final tem gade. N late submissins f HW will be accepted as the slutins will be psted n the day they ae cllected. Mid-tem Examinatins (MT): Thee will be tw 50-minute mid-tem examinatins; the date and mateial cveed in each mid-tem ae listed in Cuse Outline. Each mid-tem is cunted as 5% f yu final tem gade. inal Examinatin (L): inal examinatin will be a cmpehensive examinatin, cveing the mateial taught in the entie tem. It will be cunted as 30% f yu final tem gade. Tem Gade: Tem gade will be calculated based n 0% f CA, 0% f HW, 5% f each MT, and 30% f L. inal lette gade will be assigned based n 00% A 90% > B 80% > C 70% > D 60% >. Thee will be n gade cuving. Hweve, a student wh eans a gade 90% highe in his/he final examinatin will autmatically eceive an A gade f the cuse. 3
0 Engineeing Mechanics - Statics Chapte Geneal Pinciples Scala : Vect : Bk a a By hand a a SI U.S. Mass M kilgam kg slug Length L mete m feet ft ce Newtn N pund lb Time T secnd s secnd sec 4
0 Engineeing Mechanics - Statics Methd f Pblem Slving. ead the pblem caefully.. Identify the esult equested. 3. Identify the pinciples t be used t btain the esult. 4. Pepae a scaled sketch (e.g., a fee-bdy diagam) and tabulate the infmatin pvided. 5. Apply the apppiate pinciples and equatins. 6. ept the answe with the apppiate numbe f significant figues and the apppiate units. 7. Study the answe and detemine if it is easnable. 5
0 Engineeing Mechanics - Statics Gd Bad 6
0 Engineeing Mechanics - Statics Chapte Cncuent ce Systems 7
0 Engineeing Mechanics - Statics. Intductin A physical bdy subjected t a pai f lads The bdy is simplified t a paticle paticle mechanics The bdy defms, may fail eventually The Bdy des nt defm igid bdy mechanics tdec Physics 30 Mechanics f Mateials 0 Statics 8
0 Engineeing Mechanics - Statics. ces and Thei Chaacteistics A fce is a vect; it has () magnitude, () diectin, and (3) a pint f applicatin A fee vect A sliding vect A bund vect In Statics fces ae teated as sliding vects 9
0 Engineeing Mechanics - Statics. ces and Thei Chaacteistics Pinciple f Tansmissibility The extenal effect f a fce n a igid bdy is the same f all pints f applicatin f the fce alng its line f actin. Pinciple f Tansmissibility is applicable t igid-bdy mechanics. Theefe, in Statics fces ae teated as sliding vects. 0
0 Engineeing Mechanics - Statics. ces and Thei Chaacteistics Classificatin f ces. Cncuent ces 5. Geneal ces z L. Cplane ces O y x 3. Paallel ces n 4. Cllinea ces 0 i ma Statics Dynamics
0 Engineeing Mechanics - Statics.3 esultant f Tw Cncuent ces (Paallelgams and Laws f Sines and Csines) Pinciple f Tansmissibility φ β γ α φ φ : Angle between and + + β : Angle between and γ π φ; α φ β π β γ
0 Engineeing Mechanics - Statics.3 esultant f Tw Cncuent ces (Paallelgams and Laws f Sines and Csines) φ γ α β φ γ π φ α φ β π β γ sinγ Use Law f + sin β sin β sinγ β a c a Law f Sines : sinα Law f Csines : c + sin csφ ( π φ) a γ α b b sin β + b Csines t detemine the magnitude f csγ + cs Use Law f Sines t detemine the diectin f sin β + c sinγ abcsγ ( π φ) sinφ 3
0 Engineeing Mechanics - Statics.3 esultant f Tw Cncuent ces (Paallelgams and Laws f Sines and Csines - Examples) 800 lb 56º y y φ β 600 N 40º 35º 500 lb 900 N x x φ 80 56 500 + + 800 665.3lb β sin φ 40 900 + 4 + + csφ sinφ sin + 600,43 N β sin + 3 ( 500)( 800) cs( 4 ) 44.6 0 + csφ sinφ sin Hmewk: Pblems -3, -, -6 800 sin4 665.3 85.5 3 ( 900)( 600) cs( 40 ).997 0 600 sin 40 43 5.8 4
0 Engineeing Mechanics - Statics.4 esultant f Thee Me Cncuent ces (Paallelgams and Laws f Sines and Csines) + 3 + 3 3 3 + 3 3 3 3 3 + 3 + + + + 3 5
0 Engineeing Mechanics - Statics.4 esultant f Thee Me Cncuent ces (Paallelgams and Laws f Sines and Csines - Example) Detemine the esultant f,, and 3 fces Step : + 3 Step: + φ 30 + 30 60 φ 7 + 40 67 + + csφ 954 lb sinφ β sin 7.0 + 3 + 3 csφ,386 lb sinφ β sin θ 39.3 + 0 59.3 39.3 Hmewk: Pblems -9, -4, -8 6