Page 194 - Analysis and Design of Energy Geostructures
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Deformation in the context of energy geostructures  167



                   2. Four stress strain relations
                                              1
                                       8
                                                       ð
                                                                     ð
                                       >  ε rr 5  ½ σ rr 2 νσ zz 1 σ θθ ފ 2 α T 2 T 0 Þ
                                       >
                                       >
                                       >
                                              E
                                       >
                                       >
                                               1
                                       >
                                       >
                                       >
                                         ε zz 5
                                       >
                                                                     ð
                                                        ð
                                       >        ½ σ zz 2 νσ rr 1 σ θθ ފ 2 α T 2 T 0 Þ
                                       >
                                       <
                                               E
                                                                                         ð4:65Þ
                                               1
                                         ε θθ 5
                                       >
                                                                     ð
                                                       ð
                                       >        ½ σ zz 2 νσ rr 1 σ zz ފ 2 α T 2 T 0 Þ
                                       >
                                       >
                                       >
                                              E
                                       >
                                       >
                                       >
                                                       ε rz 5
                                       >
                                       >                    σ rz
                                       >
                                       >
                                       :
                                                            2G
                   3. Four strain displacement relations
                                                     ε rr 52  @u
                                                             @r
                                                     ε zz 52  @w
                                                             @z
                                                                                         ð4:66Þ
                                                      ε θθ 52  u
                                                              r
                                                                  !
                                                ε rz 52  1 @u  1  @w
                                                       2 @z     @x
                   4. Boundary conditions
                         In the two-dimensional case, traction boundary conditions, considering the sur-
                      face of the body as traction-free, take the following form
                                                 (
                                                    σ rr n r 1 σ rz n z 5 0
                                                                                         ð4:67Þ
                                                   σ rz n r 1 σ zz n z 5 0
                         For displacement boundary conditions

                                                      u 5 F 1 ðHÞ
                                                                                         ð4:68Þ
                                                      w 5 F 2 ðHÞ
                   4.9.6 One-dimensional thermoelastic modelling
                   Modelling thermoelastic problems with reference to one-dimensional conditions may
                   be of interest in some situations. A one-dimensional analysis approach is proposed in
                   the following by assuming that a temperature distribution of the form T 5 TðzÞ is
                   known.
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