### Abstract

In conventional theory, it is assumed that continuum state can be determined instantaneously. This assumption restricts the arguments for quantities of state and constitutive equations. In a previous paper, noninstantaneities were introduced in the laws of thermodynamics, to express the constitutive equation of stress including the effect of viscoelastisity. In this paper, we discuss that nonequilibrium processes can be expressed by means of this concept of noninstantaneities in continuum mechanics. The 1st and 2nd laws of thermodynamics are expressed considering the effect of the nonistantaneities of thermodynamic quantities. Then a balance law for the newly defined entropy flux in this paper, is formulated to make the balance equation system complete. Furthermore, the Clausius-Duhem inequality that characterizes materials with the noninstantaneous state is derived. On the basis of the Clausius-Duhem inequality, it is suggested that the constitutive equation of stress restricted thermodynamically, depends on the time rate of the temperature for the nonequilibrium processes.

Original language | English |
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Pages (from-to) | 225-231 |

Number of pages | 7 |

Journal | Transactions of the Japan Society of Mechanical Engineers Series A |

Volume | 59 |

Issue number | 557 |

DOIs | |

Publication status | Published - 1993 Jan 1 |

Externally published | Yes |

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### Keywords

- Constitutive Equation
- Continuum Mechanics
- Entropy
- Memory
- Nonequilibrium
- Noninstantaneity
- Thermal Stress
- Thermodynamics
- Thermomechanics

### ASJC Scopus subject areas

- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering

### Cite this

*Transactions of the Japan Society of Mechanical Engineers Series A*,

*59*(557), 225-231. https://doi.org/10.1299/kikaia.59.225