### Abstract

Bending an elastic beam leads to a complicated 3D stress distribution, but the shear and transverse stresses are so small in a slender beam that a good approximation is obtained by assuming purely uniaxial stress. In this paper, we demonstrate that the same is true for a saturated poroelastic beam. Previous studies of poroelastic beams have shown that, to satisfy the Beltrami-Michell compatibility conditions, it is necessary to introduce either a normal transverse stress or shear stresses in addition to the bending stress. The problem is further complicated if lateral diffusion is permitted. In this study, a fully coupled finite element analysis (FEA) incorporating the lateral diffusion effect is presented. Results predicted by the "exact" numerical solution, including load relaxation, pore pressure, stresses and strains, are compared to an approximate analytical solution that incorporates the assumptions of simple beam theory. The applicability of the approximate beam-bending solution is investigated by comparing it to FEA simulations of beams with various aspect ratios. For "beams" with large width-to-height ratios, the Poisson effect causes vertical deflections that cannot be neglected. It is suggested that a theory of plate bending is needed in the case of poroelastic media with large width-to-height ratios. Nevertheless, use of the approximate solution yields very small errors over the range of width-to-height ratios (viz., 1-4) explored with FEA.

Original language | English (US) |
---|---|

Pages (from-to) | 3451-3462 |

Number of pages | 12 |

Journal | International Journal of Solids and Structures |

Volume | 46 |

Issue number | 18-19 |

DOIs | |

State | Published - Sep 2009 |

Externally published | Yes |

### Fingerprint

### Keywords

- Beams and columns
- Finite elements
- Porous material
- Strain compatibility
- Stress relaxation

### ASJC Scopus subject areas

- Mechanical Engineering
- Mechanics of Materials
- Materials Science(all)
- Condensed Matter Physics
- Applied Mathematics
- Modeling and Simulation

### Cite this

*International Journal of Solids and Structures*,

*46*(18-19), 3451-3462. https://doi.org/10.1016/j.ijsolstr.2009.05.016

**Bending of a poroelastic beam with lateral diffusion.** / Scherer, George W.; Prévost, Jean H.; Wang, Zhihua.

Research output: Contribution to journal › Article

*International Journal of Solids and Structures*, vol. 46, no. 18-19, pp. 3451-3462. https://doi.org/10.1016/j.ijsolstr.2009.05.016

}

TY - JOUR

T1 - Bending of a poroelastic beam with lateral diffusion

AU - Scherer, George W.

AU - Prévost, Jean H.

AU - Wang, Zhihua

PY - 2009/9

Y1 - 2009/9

N2 - Bending an elastic beam leads to a complicated 3D stress distribution, but the shear and transverse stresses are so small in a slender beam that a good approximation is obtained by assuming purely uniaxial stress. In this paper, we demonstrate that the same is true for a saturated poroelastic beam. Previous studies of poroelastic beams have shown that, to satisfy the Beltrami-Michell compatibility conditions, it is necessary to introduce either a normal transverse stress or shear stresses in addition to the bending stress. The problem is further complicated if lateral diffusion is permitted. In this study, a fully coupled finite element analysis (FEA) incorporating the lateral diffusion effect is presented. Results predicted by the "exact" numerical solution, including load relaxation, pore pressure, stresses and strains, are compared to an approximate analytical solution that incorporates the assumptions of simple beam theory. The applicability of the approximate beam-bending solution is investigated by comparing it to FEA simulations of beams with various aspect ratios. For "beams" with large width-to-height ratios, the Poisson effect causes vertical deflections that cannot be neglected. It is suggested that a theory of plate bending is needed in the case of poroelastic media with large width-to-height ratios. Nevertheless, use of the approximate solution yields very small errors over the range of width-to-height ratios (viz., 1-4) explored with FEA.

AB - Bending an elastic beam leads to a complicated 3D stress distribution, but the shear and transverse stresses are so small in a slender beam that a good approximation is obtained by assuming purely uniaxial stress. In this paper, we demonstrate that the same is true for a saturated poroelastic beam. Previous studies of poroelastic beams have shown that, to satisfy the Beltrami-Michell compatibility conditions, it is necessary to introduce either a normal transverse stress or shear stresses in addition to the bending stress. The problem is further complicated if lateral diffusion is permitted. In this study, a fully coupled finite element analysis (FEA) incorporating the lateral diffusion effect is presented. Results predicted by the "exact" numerical solution, including load relaxation, pore pressure, stresses and strains, are compared to an approximate analytical solution that incorporates the assumptions of simple beam theory. The applicability of the approximate beam-bending solution is investigated by comparing it to FEA simulations of beams with various aspect ratios. For "beams" with large width-to-height ratios, the Poisson effect causes vertical deflections that cannot be neglected. It is suggested that a theory of plate bending is needed in the case of poroelastic media with large width-to-height ratios. Nevertheless, use of the approximate solution yields very small errors over the range of width-to-height ratios (viz., 1-4) explored with FEA.

KW - Beams and columns

KW - Finite elements

KW - Porous material

KW - Strain compatibility

KW - Stress relaxation

UR - http://www.scopus.com/inward/record.url?scp=67649950290&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=67649950290&partnerID=8YFLogxK

U2 - 10.1016/j.ijsolstr.2009.05.016

DO - 10.1016/j.ijsolstr.2009.05.016

M3 - Article

AN - SCOPUS:67649950290

VL - 46

SP - 3451

EP - 3462

JO - International Journal of Solids and Structures

JF - International Journal of Solids and Structures

SN - 0020-7683

IS - 18-19

ER -