金属基弥散燃料元件失稳肿胀的静态弹塑性模型

针对金属基弥散燃料元件金属基体开裂导致的失稳肿胀，在不考虑粘塑性变形情况下建立了裂纹面的静态弹塑性模型，采用有限元模拟对静态弹塑性模型进行了验证。当金属基体发生全屈服后，其主要变形方式从弹性变形转变为塑性变形；根据金属基体的主要变形方式，分别建立金属基弥散燃料裂纹面的弹性变形模型和塑性变形模型；结合内应力与弯矩的平衡条件，获得了裂纹面弹塑性变形的临界转变条件。弹性变形模型和塑性变形模型的计算结果与有限元模拟结果符合较好，验证了金属基弥散燃料失稳肿胀的静态弹塑性模型的有效性。 

Static Elastoplastic Model of Metal Matrix Dispersion Fuel Element under Unstable Swelling Condition

For the unstable swelling of metal matrix dispersion fuel element induced by the cracking of metal matrix, the static elastoplastic model of crack surface was established without considering viscoplastic deformation, and this model was verified by the finite element simulation. The primary deformation mode transformed from elastic deformation into plastic deformation after the metal matrix completely yielded. The elastic and plastic deformation models of crack surface were established respectively based on the primary deformation modes of metal matrix. According to the balance between internal stress and bending moment, the critical transformation condition of elastic/plastic deformation was obtained. The calculated results of elastic and plastic deformation models fitted well with the finite element simulation, verifying the availability of the static elastoplastic model of metal matrix dispersion fuel under unstable swelling condition.