Techniques or processes for providing markings on products are disclosed. In one embodiment, the products have housings and the markings are to be provided on sub-surfaces of the housings. For example, a housing for a particular product can include an outer housing surface and the markings can be provided on a sub-surface the outer housing surface yet still be visible from the outside of the housing. Since the markings are beneath the surface of the housing, the markings are durable.

The present invention discloses a method and system for controlling axial length of an ellipsoidal shell based on liquid volume loading. The method includes: determining the volume calculation models of an unformed prefabricated shell and a formed ellipsoidal shell; determining a calculation model of a volume difference between the unformed prefabricated shell and the formed ellipsoidal shell; determining a structure size of the unformed prefabricated shell according to a target axial length of the formed ellipsoidal shell; obtaining the volume difference between the formed ellipsoidal shell and the unformed prefabricated shell, and recording the volume difference as a target volume; injecting liquid into the unformed prefabricated shell with target volume to obtain the formed ellipsoidal shell. The forming process in the present invention is simple and easy to implement without considering differences in materials and wall thicknesses and can control and adjust the axial length dimension accuracy of a shell.

The present invention discloses a method and system for controlling axial length of an ellipsoidal shell based on liquid volume loading. The method includes: determining the volume calculation models of an unformed prefabricated shell and a formed ellipsoidal shell; determining a calculation model of a volume difference between the unformed prefabricated shell and the formed ellipsoidal shell; determining a structure size of the unformed prefabricated shell according to a target axial length of the formed ellipsoidal shell; obtaining the volume difference between the formed ellipsoidal shell and the unformed prefabricated shell, and recording the volume difference as a target volume; injecting liquid into the unformed prefabricated shell with target volume to obtain the formed ellipsoidal shell. The forming process in the present invention is simple and easy to implement without considering differences in materials and wall thicknesses and can control and adjust the axial length dimension accuracy of a shell.

The present invention discloses a method and system for controlling axial length of an ellipsoidal shell based on liquid volume loading. The method includes: determining the volume calculation models of an unformed prefabricated shell and a formed ellipsoidal shell; determining a calculation model of a volume difference between the unformed prefabricated shell and the formed ellipsoidal shell; determining a structure size of the unformed prefabricated shell according to a target axial length of the formed ellipsoidal shell; obtaining the volume difference between the formed ellipsoidal shell and the unformed prefabricated shell, and recording the volume difference as a target volume; injecting liquid into the unformed prefabricated shell with target volume to obtain the formed ellipsoidal shell. The forming process in the present invention is simple and easy to implement without considering differences in materials and wall thicknesses and can control and adjust the axial length dimension accuracy of a shell.

The present invention discloses a method and system for controlling axial length of an ellipsoidal shell based on liquid volume loading. The method includes: determining the volume calculation models of an unformed prefabricated shell and a formed ellipsoidal shell; determining a calculation model of a volume difference between the unformed prefabricated shell and the formed ellipsoidal shell; determining a structure size of the unformed prefabricated shell according to a target axial length of the formed ellipsoidal shell; obtaining the volume difference between the formed ellipsoidal shell and the unformed prefabricated shell, and recording the volume difference as a target volume; injecting liquid into the unformed prefabricated shell with target volume to obtain the formed ellipsoidal shell. The forming process in the present invention is simple and easy to implement without considering differences in materials and wall thicknesses and can control and adjust the axial length dimension accuracy of a shell.

A toroid pressure vessel includes a toroid body having an inner shell and an outer shell. The toroid body includes a toroid outer perimeter. The outer shell extends along the toroid outer perimeter. A planar exterior face extends along at least a portion of the outer shell and the toroid outer perimeter. A support belt circumscribes the toroid outer perimeter and is coupled along the planar exterior face. The support belt braces and supports the pressure vessel along the toroid outer perimeter against bulging force (and hoop stress) generated by pressurized fluids within the vessel. The support belt facilitates the use of thinner pressure vessel shells and thereby decreases the weight of the pressure vessel while providing a support to the outer shell that substantially prevents deformation of the planar exterior face.