Nested article by additive manufacturing with non-removable internal supporting structure

A fuel injector device for a gas turbine, the fuel injector device comprising:

• a body having two lateral surfaces extending along a longitudinal direction and a crosswise direction;
• the body being streamlined for use in a fluid flow and the lateral surfaces joined to one another at an upstream side form a leading edge of the body and the lateral surfaces joined to one another at a downstream side to form a trailing edge of the body;
• a shell defining a gas fuel plenum, the shell nested within the lateral surfaces, wherein the shell is configured to provide a gas fuel flow into the fluid flow;
• an oil fuel duct, the oil fuel duct elongated in the longitudinal direction, the oil fuel duct nested within the shell, wherein the oil fuel duct is configured to provide an oil fuel flow into the fluid flow;
• an array of ribs extending between the shell and the oil fuel duct, wherein the array of ribs are configured to compensate differential elongation of the nested oil fuel duct with respect to the shell along the crosswise direction by flexural deformation;
• struts supported within the lateral surfaces for supporting the shell;
• and
• a cut defined between the struts and a wall structure, the wall structure delimiting a cooling air plenum,
• wherein the body, the shell and the oil fuel duct are additively manufactured.