电子教案与课件：materialsselection

Titelmasterformat durch Klicken bearbeiten,Textmasterformate durch Klicken bearbeiten,Zweite Ebene,Dritte Ebene,Vierte Ebene,Fnfte Ebene,*,*,*,MATERIALS SELECTION,ECONOMIC, ENVIRON., & DESIGN ISSUES,ISSUES TO ADDRESS., Price and availability of materials,., How do we select materials based on optimal,performance?, Applications:,-shafts under torsion,-bars under tension,-plates under bending,-materials for a magnetic coil.,MATERIALS SELECTIONECONOMIC,Chapter 22-,2, Current Prices on the web,(a),:,-Short term trends: fluctuations due to supply/demand.,-Long term trend: prices will increase as rich deposits,are depleted., Materials require energy to process them:,-Energy to produce,materials (GJ/ton),Al,PET,Cu,steel,glass,paper,237,(17),(b),103,(13),(c),97,(20),(b),20,(d),13,(e),9,(f),-Cost of energy used in,processing materials ($/GJ),(g),elect resistance,propane,natural gas,oil,25,11,9,8,a http:/www.statcan.ca/english/pgdb/economy/primary/prim44.htm,a ,b http:/www.automotive.copper.org/recyclability.htm,c http:/www.steel.org.facts/power/energy.htm,e http:/eren.doe.gov/EE/industry_glass.html,f http:/www.aifq.qc.ca/english/industry/energy.html#1,g http:/www.wren.doe.gov/consumerinfo/rebriefs/cb5.html,Energy using recycled,material indicated in green.,PRICE AND AVAILABILITY,Chapter 22-2 Current Prices,Chapter 22-,3, Reference material:,-Rolled A36 plain,carbon steel., Relative cost,$,fluctuates less,over time than,actual cost.,Based on data in Appendix,C,Callister, 6e,.,AFRE, GFRE, & CFRE,= Aramid,Glass, & Carbon fiber reinforced epoxy composites.,RELATIVE COST,$, OF MATERIALS,Chapter 22-3 Reference materi,4, Bar must not lengthen by more than,d,under force F; must have initial length L., Maximize the,Performance Index,:,- Stiffness relation:,- Mass of bar:,(,s,= E,e,), Eliminate the free design parameter,c,:,specified by application,minimize for small M,(stiff, light tension members),STIFF,&,LIGHT,TENSION MEMBERS,4 Bar must not lengthen by m,5, Bar must carry a force F without failing;,must have initial length L., Maximize the,Performance Index,:,- Strength relation:,- Mass of bar:, Eliminate the free design parameter,c,:,specified by application,minimize for small M,(strong, light tension members),STRONG,&,LIGHT,TENSION MEMBERS,5 Bar must carry a force F w,6, Bar must carry a moment, M,t,;,must have a length L., Maximize the,Performance Index,:,- Strength relation:,- Mass of bar:, Eliminate the free design parameter,R,:,specified by application,minimize for small M,(strong, light torsion members),STRONG & LIGHT,TORSION,MEMBERS,6 Bar must carry a moment, M,Chapter 22-,DATA: STRONG & LIGHT TENSION/TORSION MEMBERS,Increasing P,for strong,tension,members,Increasing P,for strong,torsion members,0.1,1,10,3,0,1,10,10,2,10,3,10,4,Density,r,(Mg/m,3,),Strength,s,f,(MPa),slope = 1,0.1,Metal,alloys,Steels,Ceramics,PMCs,Polymers,| grain,grain,wood,Cermets,slope = 3/2,7,Adapted from Fig. 6.22,Callister 6e,. (Fig. 6.22 adapted from M.F. Ashby,Materials Selection in Mechanical Design, Butterworth-Heinemann Ltd., 1992.),Chapter 22-DATA: STRONG & LIG,Chapter 22-,0.1,1,10,3,0,0.1,1,10,10,2,10,3,10,4,Cermets,Steels,Density,r,(Mg/m,3,),Strength,s,f,(MPa),slope = 2,Increasing P,for strong,bending members,Metal,alloys,Ceramics,PMCs,Polymers,| grain,grain,wood,8, Maximize the,Performance Index,:,Adapted from Fig. 6.22,Callister 6e,. (Fig. 6.22 adapted from M.F. Ashby,Materials Selection in Mechanical Design, Butterworth-Heinemann Ltd., 1992.),DATA: STRONG & LIGHTBENDING MEMBERS,Chapter 22-0.1 1 10 3 0,Chapter 22-,9, Other factors:,-require,s,f, 300MPa.,-Rule out ceramics and glasses: K,Ic,too small., Maximize the,Performance Index,:, Numerical Data:, Lightest: Carbon fiber reinf. epoxy,(CFRE) member.,material,CFRE (v,f,=0.65),GFRE (v,f,=0.65),Al alloy (2024-T6),Ti alloy (Ti-6Al-4V),4340 steel (oil,quench & temper),r,(Mg/m,3,),1.5,2.0,2.8,4.4,7.8,P (MPa),2/3,m,3,/Mg),73,52,16,15,11,Data from Table 6.6,Callister 6e,.,t,f,(MPa),1140,1060,300,525,780,DETAILED STUDY I: STRONG, LIGHT TORSION MEMBERS,Chapter 22-9 Other factors:,Chapter 22-,10, Minimize Cost:,Cost Index M,$,$,/P,(since M 1/P), Numerical Data:, Lowest cost: 4340 steel (oil quench & temper),material,CFRE (vf=0.65),GFRE (vf=0.65),Al alloy (2024-T6),Ti alloy (Ti-6Al-4V),4340 steel (oil,quench & temper),$,80,40,15,110,5,P (MPa),2/3,m,3,/Mg),73,52,16,15,11,(,$,/P)x100,112,76,93,748,46, Need to consider machining, joining costs also.,Data from Table 6.7,Callister 6e,.,DETAILED STUDY I: STRONG, LOW COST TORSION MEMBERS,Chapter 22-10 Minimize Cost:,Chapter 22-,11, Background,(2),: High magnetic fields permit study of:,-electron energy levels,-conditions for superconductivity,-conversion of insulators into conductors., Largest Example:,-short pulse of 800,000 gauss,(Earths magnetic field: 0.5 Gauss), Technical Challenges,:,-Intense resistive heating,can melt the coil.,-Lorentz stress can exceed,the material strength., Goal: Select an optimal coil material.,(1),Based on discussions with Greg Boebinger, Dwight Rickel, and James Sims, National High Magnetic Field Lab (NHMFL), Los Alamos National Labs, NM (April, 2002).,(2),See G. Boebinger, Al Passner, and Joze Bevk, Building World Record Magnets, Scientific American, pp. 58-66, June 1995, for more information.,Pulsed,magnetic,capable of,600,000 gauss,field during,20ms period.,Fractured,magnet,coil.,(Photos,taken at NHMFL,Los Alamos,National Labs,NM (Apr. 2002),by P.M. Anderson),DETAILED STUDY II: OPTIMAL MAGNET COIL MATERIAL,Chapter 22-11 Background(2):,Chapter 22-,12, Applied magnetic field, H:,H = N I/L, Lorentz hoop stress:, Resistive heating:,(adiabatic),temp increase,during current,pulse of,D,t,Magnetic,field,points,out of,plane.,elect. resistivity,specific heat,LORENTZ STRESS & HEATING,Chapter 22-12 Applied magnet,Chapter 22-,13, Mass of coil:,M =,r,d,AL, Eliminate free design parameters,A,I,from the,stress & heating equations,(previous slide),:, Applied magnetic field:,H = N I/L,-Stress requirement,specified by application,Performance Index P,1,:,maximize for large H,2,/M,specified by application,Performance Index P,2,:,maximize for large Ht,1/2,/M,-Heating requirement,MAGNET COIL:,PERFORMANCE INDEX,Chapter 22-13 Mass of coil:M,Chapter 22-,14, Relative cost of coil:,$ =,$,M, Eliminate M from the stress & heating equations:, Applied magnetic field:,H = N I/L,-Stress requirement,specified by application,Cost Index C,1,:,maximize for,large H,2,/$,specified by application,Cost Index C,2,:,maximize for,large Ht,1/2,/$,-Heating requirement,MAGNET COIL:,COST INDEX,Chapter 22-14 Relative cost,Chapter 22-,15, Data from Appendices B and C,Callister 6e,:,Material,1020 steel (an),1100 Al (an),7075 Al (T6),11000 Cu (an),17200 Be-Cu (st),71500 Cu-Ni (hr),Pt,Ag (an),Ni 200,units,s,f,395,90,572,220,475,380,145,170,462,MPa,r,d,7.85,2.71,2.80,8.89,8.25,8.94,21.5,10.5,8.89,g/cm,3,$,0.8,12.3,13.4,7.9,51.4,12.9,1.8e4,271,31.4,-,c,v,486,904,960,385,420,380,132,235,456,J/kg-K,r,e,1.60,0.29,0.52,0.17,0.57,3.75,1.06,0.15,0.95,W,-m,3,P,1,50,33,204,25,58,43,7,16,52,s,f,/,r,d,P,2,2,21,15,5,3,1,19,1,2,(c,v,/,r,e,),0.5,r,d,C,1,63,3,15,3,1,3,1,1,2,P,1,/,$,C,2,2.5,1.7,1.1,0.6,0.1,0.1,0.1,0.1,0.1,P,2,/,$,Avg. values used. an = annealed; T6 = heat treated ,st = solution heat treated; hr = hot rolled, Lightest for a given H: 7075 Al (T6), Lightest for a given H(,D,t),0.5,: 1100 Al (an), Lowest cost for a given H: 1020 steel (an), Lowest cost for a given H(,D,t),0.5,: 1020 steel (an),C,2,C,1,P,2,P,1,INDICES FOR A COIL MATERIAL,Chapter 22-15 Data from Appe,Chapter 22-,16, Material costs fluctuate but rise over the long,term as:,-rich deposits are depleted,-energy costs increase., Recycled materials reduce energy use significantly., Materials are selected based on:,-,performance,or,cost indices,., Examples:,-design of minimum mass, maximum strength of:, shafts under torsion, bars under tension, plates under bending,-selection of materials to optimize more than one,property:, material for a magnet coil., analysis does not include cost of operating the magnet.,SUMMARY,Chapter 22-16 Material costs,