Independent tank with curvature change section, and manufacturing method for independent tank

A method of manufacturing an independent tank which includes at least one curvature change portion in which a curvature along an axial direction of plate members that form the tank changes along the axial direction, a first plate member including a transition portion that has a varying plate thickness toward an end, the first plate member having a cylindrical shape, and a second plate member having a higher curvature along the axial direction than the first plate member, the second plate member having a hemispherical shape, the method comprising the processes of:

• preparing the first plate member so that both an inner peripheral surface and an outer peripheral surface of the first plate member are not flush with an inner peripheral surface and an outer peripheral surface of the second plate member having a higher curvature, respectively, and a plate thickness center of the plate member is offset toward a radial inner side or a radial outer side with respect to a plate thickness center of the second plate member;
• and
• joining the end of the first plate member and an end of the second plate member having a higher curvature together.

A method of manufacturing an independent tank which includes at least one curvature change portion in which a curvature along an axial direction of plate members that form the tank changes along the axial direction, a first plate member including a transition portion that has a varying plate thickness toward an end, the first plate member having a cylindrical shape, and a second plate member having a higher curvature along the axial direction than the first plate member, the second plate member having a hemispherical shape, the method comprising the processes of:

• preparing the first plate member so that both an inner peripheral surface and an outer peripheral surface of the first plate member are not flush with an inner peripheral surface and an outer peripheral surface of the second plate member, respectively, and a plate thickness center of the first plate member is offset toward a radial outer side from a position where stress that occurs at an outer surface of the tank and stress that occurs at an inner surface of the tank become equal to each other, with respect to a plate thickness center of the second plate member;
• and
• joining the first plate member and the second plate member together.

A method of manufacturing an independent tank which includes at least one curvature change portion in which a curvature along an axial direction of plate members that form the tank changes along the axial direction, a first plate member including a transition portion that has a varying plate thickness toward an end, the first plate member having a cylindrical shape, and a second plate member having a higher curvature along the axial direction than the first plate member, the second plate member having a hemispherical shape, the method comprising the processes of:

• preparing the first plate member so that both an inner peripheral surface and an outer peripheral surface of the first plate member are not flush with an inner peripheral surface and an outer peripheral surface of the second plate member, respectively, and a plate thickness center of the first plate member is offset toward a radial outer side from a position where stress that occurs at an outer surface of the tank and stress that occurs at an inner surface of the tank become equal to each other, with respect to a plate thickness center of the second plate member;
• and
• joining the first plate member and the second plate member together.

A method of manufacturing an independent tank which includes at least one curvature change portion in which a curvature along an axial direction of plate members that form the tank changes along the axial direction, a first plate member including a transition portion that has a varying plate thickness toward an end, the first plate member having a cylindrical shape, and a second plate member having a higher curvature along the axial direction than the first plate member, the second plate member having a hemispherical shape, the method comprising the processes of:

• preparing the first plate member so that both an inner peripheral surface and an outer peripheral surface of the first plate member are not flush with an inner peripheral surface and an outer peripheral surface of the second plate member, respectively, and a plate thickness center of the first plate member is offset toward a radial outer side from a plate thickness center of the second plate member to be at a position where stress that occurs at an outer surface of the tank and stress that occurs at an inner surface of the tank become equal to each other;
• and
• joining the first plate member and the second plate member having a higher curvature together.