{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Homework Solution 8

Homework Solution 8 - Chapter 1| Solution 221 The average...

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Chapter 1|], Solution 221 The average molecularmass ofa t'nenmplastic directly affects its strength as it is indicative ofthe degree of polymerization of the solid; the plastic must attain a critical molecular mass to become a stable solid. However, increalug the mass beyond this minima dees not appreciably increase the thermoplastic’s strengdl. Chapter 1|], Solution 222 (a) As the amount ofcrystallinity increases, the polymer chains become more tightly packed and the tensile strength increases. {b} The tensile modulus of elasticity is also directly related to crystallinity; the modulus increases with increasing mommie- [c] Increased crystallinity corresponds to an increase in density. Chapter 1|], Solution 223 Low-density polyethylene is weaker than high—density because the molecular chains are more branched and farther apart fiem each other= causing weaker bonding forces and thus lower strength. Chapter 1|], Solution 223 In general, thermosetting plastics have high strengths and low ductililies because their molecular structure is oounraised ofa covalently bonded networkpr‘oduced by chemical reaction within the material after casting or during pressing underheat and pressure. Chapter 11, Solution fit} The lack ofplasticity in crystalline ceramics is attributed to their ionic and covalent chemical bonds. In covalent crystals and covalently bended ceramics, atoms bond thrtough the exchange of electron charge between pairs of electrons, in a specific and directional manner. Consequently, if the oeramic is sufficiently stressed, electron-pair bonds undergo irreparable separation, causing the material to experience britde fiacture. Chapter 11, Solution 53 (a) Pores serve as a source for stress induced crack imfiaflmpropagafim andreduce the cross-sectional area available for load application- Crmsequently, as the porosity of a ceramic material increases, the material tensile strength decreases- [b] Foraporosity-fi’eeoeramitheflawsiae,andthnstheslrmgflr,issolelyafi1nctionofgrainsize;fl1efinerthe grain size,thesmallertheflauaatgrainboundarisnandthe greatertheceramictensile strength. Chapter 11, Solution E? (a) Thelargestedgeersurfacecrackis equalton: o 2 E _ o=i —IC = —3'EMP3_‘JE =".I"_23:=-::lfl"5 m='l'.23,um It For! HHSD MPa} {b} The stress which will cause failure is: r: of: l [i]=1[—12'5MPEll m]=ldflthPa «its J1? I oilfield—Em Chapter 12, Solution 25 a, = Er?! +E,,rr,, ={rt5x1ot petrosstfiossmot patter?) = 11.53 2-: 113‘5 psi = 110.9 GPa Chapter 12, Solution 23 a EIEM [34:] GPade can c: = —=11.sscpa 153.3,, + ems! roaster are) +(o_ss)(34o GPa) Chapter 12, Solution tld Emmp = .fsicEsrc +fensrr Essen where fsnsr; = 1 — feic rso GPa = fmr rss GPa]+[l— figurines) f,,,, = sass ...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern