The invention provides a sonotrode (100) for welding a material, the sonotrode (100) comprising a welding section (110) configured for contacting the material, wherein the welding section (110) defines a rounded shape (111) in a cross-section parallel to a longitudinal axis (A) of the sonotrode (100), wherein the rounded shape (111) approximates a circular sector (20), wherein the circular sector (20) has a central angle α.sub.c selected from the range of 25°-300°, and wherein the circular sector (20) has a central radius r.sub.c selected from the range of 5-30 mm, and wherein the sonotrode (100) has a width W perpendicular to the longitudinal axis (A) [and to the cross-section], wherein W is selected from the range of 10-100 mm.

The invention provides a sonotrode (100) for welding a material, the sonotrode (100) comprising a welding section (110) configured for contacting the material, wherein the welding section (110) defines a rounded shape (111) in a cross-section parallel to a longitudinal axis (A) of the sonotrode (100), wherein the rounded shape (111) approximates a circular sector (20), wherein the circular sector (20) has a central angle α.sub.c selected from the range of 25°-300°, and wherein the circular sector (20) has a central radius r.sub.c selected from the range of 5-30 mm, and wherein the sonotrode (100) has a width W perpendicular to the longitudinal axis (A) [and to the cross-section], wherein W is selected from the range of 10-100 mm.

A duct for a ducted-rotor aircraft may include an internal structure and an aerodynamic exterior skin that is adhesively bonded to the internal structure. The skin may include a leading-edge portion disposed at an inlet of the duct and an inner portion disposed along an interior of the duct. The inner portion of the skin may be bonded to the internal structure with a first bondline of adhesive and the leading-edge portion of the skin may be bonded to the inner portion of the skin with a second bondline of adhesive. One or both of the first and second bondlines of adhesive may be of non-uniform thickness to take up tolerance stackups between the inner portion of the skin, the leading-edge portion of the skin, and the internal structure.

A method of permanently joining composite parts made from thermoplastic material includes providing a first composite part and a second composite part, both made from thermoplastic material, wherein an orifice is provided in at least one of the composite parts, positioning both composite parts such that a portion of the composite part which includes the orifice is adjacent to a portion of the other composite part, injecting melted thermoplastic material through the orifice to contact the first and the second composite part in a contact area, whereby surfaces of the first and the second composite part in that contact area melt together; and solidifying the thermoplastic material in the orifice and in the contact area to permanently join the first composite part to the second composite part.

A method of permanently joining composite parts made from thermoplastic material includes providing a first composite part and a second composite part, both made from thermoplastic material, wherein an orifice is provided in at least one of the composite parts, positioning both composite parts such that a portion of the composite part which includes the orifice is adjacent to a portion of the other composite part, injecting melted thermoplastic material through the orifice to contact the first and the second composite part in a contact area, whereby surfaces of the first and the second composite part in that contact area melt together; and solidifying the thermoplastic material in the orifice and in the contact area to permanently join the first composite part to the second composite part.

Provided are a welding device and a welding method that can avoid occurrence of a clearance in a side region of a member and suppress occurrence of a failure of the member due to such a clearance. The embodiment includes: an electrode 11 configured to supply electricity to an electroconductive element 23 arranged between members 21, 22 and configured to generate heat by current conduction; and a pressing element 12 arranged in a side region of one member 22 of the members 21, 22 and configured to press the electroconductive element 23 while elastically being in close contact with the one member 22. Further, the pressing element 12 comes into close contact with the one member 22 by being pushed against the electroconductive element 23 and expanding in a direction orthogonal to a pushing direction.

Provided are a welding device and a welding method that can avoid occurrence of a clearance in a side region of a member and suppress occurrence of a failure of the member due to such a clearance. The embodiment includes: an electrode 11 configured to supply electricity to an electroconductive element 23 arranged between members 21, 22 and configured to generate heat by current conduction; and a pressing element 12 arranged in a side region of one member 22 of the members 21, 22 and configured to press the electroconductive element 23 while elastically being in close contact with the one member 22. Further, the pressing element 12 comes into close contact with the one member 22 by being pushed against the electroconductive element 23 and expanding in a direction orthogonal to a pushing direction.

A method for joining two components of a meltable material comprises the steps of providing a first component having a first border region and a second component having a second border region, placing the second component relative to the first component so as to form an overlap between the first border region and the second border region under a gap between the first border region and the second border region, continuously heating opposed sections of the first border region and the second border region at the same time through at least one energy source arranged in the gap at least partially, continuously providing a relative motion of the at least one energy source along the first border region and the second border region in the gap, and continuously pressing already heated sections of the first border region and the second border region onto each other.

A method for joining two components of a meltable material comprises the steps of providing a first component having a first border region and a second component having a second border region, placing the second component relative to the first component so as to form an overlap between the first border region and the second border region under a gap between the first border region and the second border region, continuously heating opposed sections of the first border region and the second border region at the same time through at least one energy source arranged in the gap at least partially, continuously providing a relative motion of the at least one energy source along the first border region and the second border region in the gap, and continuously pressing already heated sections of the first border region and the second border region onto each other.

A method of manufacturing a composite structure, e.g. wind turbine blade, using reusable and removable perimeter plates to establish air flow channels in conjunction with a vacuum bag and mold. An exemplary setting is the perimeter of large wind blade shells where a perimeter vacuum is used to retain the part in the mold for the bonding process. The reusable plates disclosed herein create air channels whether the vacuum is introduced to the perimeter of the mold: i) through the flange in different locations; or ii) with the use of vacuum lines into the perimeter bag; or iii) built in vacuum channels in the flange of the mold.