Hybrid turbine blade including multiple insert sections

A hybrid turbine blade comprising:

• a shank portion;
• and
• an airfoil portion comprising a composite outer structure having a first mass density and a recess and at least one composite section having a first density, and at least two insert sections each having a second mass density which is less than said first mass density, the at least two insert sections disposed in alternating laminate stacked relationship with the at least one composite section and defining an alternating laminate stack of the at least one composite section and the at least two insert sections,
• wherein said alternating laminate stack of the at least one composite section and the at least two insert sections is disposed in said recess and having a major axis extending along a span of the airfoil portion, a minor axis extending along a chord of the airfoil portion and a thickness extending perpendicular to the major axis and through a thickness of the airfoil portion,
• wherein said composite outer structure and said alternating laminate stack of the at least one composite section and the at least two insert sections together define an airfoil shape, wherein said alternating laminate stack of the at least one composite section and the at least two insert sections has a stiffness and dimensional stability to maintain said airfoil shape and retain compliance and flexibility to conform to said recess,
• wherein said composite outer structure and said at least one composite section are comprised of a plurality of composite material layers comprising fiber filaments embedded in a matrix binder, and
• wherein said at least two insert sections are comprised of a material selected from the group consisting of thermoplastic materials, thermoset materials, metals, honeycomb ceramics, silicones and combinations thereof.