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Working accuracy and service life of large structural parts such as lathe beds, columns, etc. of a heavy-duty machine tool with large self-weight is directly influenced by the foundation-soil system. Therefore, simulation of the interaction of the heavy-duty machine tool and its foundation-soil system is a key technological requirement from a manufacturing perspective. However, owing to the size of the structural parts of most heavy-duty machine tools, and the complex and oversized structure of their foundation-soil system, typical simulation environments fail to meet the computational requirements. With an aim to carry out simulations and meet the computational demand for the interaction of heavy-duty machine tools and their foundation-soil system; a constitutive model with a transversely isotropic composite material (the reinforced concrete foundation) was developed to reduce computation load. Then, based on fractal theory, equations for calculating stiffness of the joint surface and damping matrix were deduced to overcome common technical difficulty facing the heavy-duty machine tool industry. Meanwhile, establishing a finite element model (FEM) framework in a cloud-computing environment, rapid solution of the FE model for heavy-duty machine tool foundation-soil system interactions was realized. Finally, a comparison of experimental results can be used to validate accuracy of the analysis. Furthermore, cloud-computing simulation of a heavy-duty machine tool foundation-soil system was used to evaluate efficacy of different types of isolation trenches. The results provide a basis for the construction of the foundations of a heavy-duty machine tool and the selection of an optimisation scheme. [ABSTRACT FROM AUTHOR]

Preload relaxation, caused by elastic interaction between tightened bolts, is one of the major reasons for non-uniformity of pretension force. But how to accurately assess the residual tension of a bolt is still extremely difficult. This paper considers two types of multiple bolted joint and six kinds of tightening sequence. Based on the deformation compatibility equation and elastic interaction stiffness, the generalized mathematical model for evaluating residual preload of bolts is established. Certain model parameters are obtained through numerical simulation. To analyze the influence of initial tightening torque, spacing between bolt holes, bolt material and gasket material on the elastic interaction stiffness, experimental devices and test procedures are developed. Furtherly, preload relaxation models are validated by tests conducted on six types of multi-bolted joint with the same surface roughness. Results of the proposed mathematical model of pretension force show a good consistency with those of corresponding experiment. • A mathematical model for estimating preload relaxation of bolted joint subjected to elastic interaction was established. • The elastic interaction stiffness between bolts was analyzed based on developed Experimental devices and test procedures. • The proposed mathematical model of pretension force shows a good consistency with the corresponding experiment. [ABSTRACT FROM AUTHOR]