A Study On FEM For Thermo-hydro Stress In Plane Viscoelastic Bodies And Its Application

Thermo-hydro stress will be induced by changes of temperature and moistite in viscoelastic material. To some problems, this stress may induce material breakage , so it's very important. The paper is divided into two parts. Firstly, the problem of plane unsteady coupl~i heat and mass transfer was studied, then the corresponding FEM progr~n was developed. Mid then, based on the result of field of temperature and moisture plane thermo-hydro viscoelastic stress was studied. a FEM formu~ for viscoelastic bodies with eight'sode isoparametric element, based integral relaxation constitutive law was given. When the material properties change with time, temperature and moisture, an integral incremental consti~itional law memoried with past strain is presented. Based the FEM formu given, the viscoelastic thermo-hydro stress program was developed. Using this program, under different drying temperature, the thermo.-hydro stress in transverse section and longitude section of corn kernel were calculated. The stress of different parts of corn kernel (lard endosperm, germ, soft endosperm) was presented and the location of the predicted tensile stress was given.