- #1

Dell

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in the following question i am asked to find the state of stress given the state of strain.

http://lh6.ggpht.com/_H4Iz7SmBrbk/SwBtHnG3qkI/AAAAAAAAB9M/rFS_orHMbGo/Capture.JPG

i went about solving this using hookes law

[tex]\sigma[/tex]xx=E[(1-v)[tex]\epsilon[/tex]

using the given

E=30*10

v=0.3

[tex]\epsilon[/tex]x=0.001

[tex]\epsilon[/tex]xy=-1.25*10

[tex]\epsilon[/tex]y=-0.005

i get

[tex]\sigma[/tex]xx=-4.6154*10

[tex]\sigma[/tex]yy=-1.8462*10

[tex]\sigma[/tex]zz=-6.9231*10

but as you can see these are not the correct answers according to the question.

can anyone see where i have gone wrong ?

also how do i find [tex]\tau[/tex]xy?

http://lh6.ggpht.com/_H4Iz7SmBrbk/SwBtHnG3qkI/AAAAAAAAB9M/rFS_orHMbGo/Capture.JPG

i went about solving this using hookes law

[tex]\sigma[/tex]xx=E[(1-v)[tex]\epsilon[/tex]

_{xx}+ v([tex]\epsilon[/tex]_{yy}+[tex]\epsilon[/tex]_{zz})]/[(1+v)1-2v)]using the given

E=30*10

^{6}v=0.3

[tex]\epsilon[/tex]x=0.001

[tex]\epsilon[/tex]xy=-1.25*10

^{-3}[tex]\epsilon[/tex]y=-0.005

i get

[tex]\sigma[/tex]xx=-4.6154*10

^{4}[tex]\sigma[/tex]yy=-1.8462*10

^{5}[tex]\sigma[/tex]zz=-6.9231*10

^{4}but as you can see these are not the correct answers according to the question.

can anyone see where i have gone wrong ?

also how do i find [tex]\tau[/tex]xy?

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