A polar functional group is added onto a surface of a metallic member. A resin member contains an adhesive functional group. The adhesive functional group and the polar functional group attract each other. A method for joining the metallic member and the resin member to each other includes: heating a junction between the metallic member and the resin member while pressing the metallic member and the resin member against each other with a first load; maintaining temperature of the junction higher than melting temperature of a resin that structures the resin member while pressing the metallic member and the resin member with each other with a second load smaller than the first load; and cooling the junction to temperature lower than the melting temperature while pressing the metallic member and the resin member against each other with a third load larger than the second load.

A polar functional group is added onto a surface of a metallic member. A resin member contains an adhesive functional group. The adhesive functional group and the polar functional group attract each other. A method for joining the metallic member and the resin member to each other includes: heating a junction between the metallic member and the resin member while pressing the metallic member and the resin member against each other with a first load; maintaining temperature of the junction higher than melting temperature of a resin that structures the resin member while pressing the metallic member and the resin member with each other with a second load smaller than the first load; and cooling the junction to temperature lower than the melting temperature while pressing the metallic member and the resin member against each other with a third load larger than the second load.

According to one aspect of the present invention, there is provided a hollow structure body having a hollow structure, in which a first shaped product constituted by a first fiber-reinforced resin material containing first reinforcing fibers and a first matrix resin and a second shaped product constituted by a second fiber-reinforced resin material containing second reinforcing fibers and a second matrix resin are combined, wherein in an arbitrary cross section in a direction perpendicular to an axial direction of the hollow structure, a ratio Sc/St between compressive strength Sc of a structure in the first shaped product and tensile strength St of a structure in the second shaped product satisfies formula (1):
(σc/σt)*(Hc/Ht)<(Sc/St)<(σt/σc)*(Hc/Ht)  formula (1).

According to one aspect of the present invention, there is provided a hollow structure body having a hollow structure, in which a first shaped product constituted by a first fiber-reinforced resin material containing first reinforcing fibers and a first matrix resin and a second shaped product constituted by a second fiber-reinforced resin material containing second reinforcing fibers and a second matrix resin are combined, wherein in an arbitrary cross section in a direction perpendicular to an axial direction of the hollow structure, a ratio Sc/St between compressive strength Sc of a structure in the first shaped product and tensile strength St of a structure in the second shaped product satisfies formula (1):
(σc/σt)*(Hc/Ht)<(Sc/St)<(σt/σc)*(Hc/Ht)  formula (1).

A method of producing a composite article is disclosed that includes generating composite plies from a low tack composite prepreg material, connecting, by an ultrasonic welding device, two or more of the composite plies by increasing their tackiness to form a composite stack, and forming, by a compression molding device, a composite article from the composite stack.

A method of producing a composite article is disclosed that includes generating composite plies from a low tack composite prepreg material, connecting, by an ultrasonic welding device, two or more of the composite plies by increasing their tackiness to form a composite stack, and forming, by a compression molding device, a composite article from the composite stack.

A flow sensor includes an auxiliary channel having an opening into which a fluid to be measured is taken; a sensor element that measures the flow of the fluid to be measured; a housing that accommodates electronic parts; and a resin cover. The flow sensor is configured such that junctions of the housing and the cover are formed in locations where first target weld portions, which are formed so that the circuit chamber is surrounded, face each other and second target weld portions, which are disposed for additional reinforcement of the joints, face each other on a bonding face of the housing and a bonding face of the cover with a step being provided. The positioning of the housing and the cover is determined, and the first target weld portions are welded to each other and second target weld portions are welded to each other by way of laser radiation.

A flow sensor includes an auxiliary channel having an opening into which a fluid to be measured is taken; a sensor element that measures the flow of the fluid to be measured; a housing that accommodates electronic parts; and a resin cover. The flow sensor is configured such that junctions of the housing and the cover are formed in locations where first target weld portions, which are formed so that the circuit chamber is surrounded, face each other and second target weld portions, which are disposed for additional reinforcement of the joints, face each other on a bonding face of the housing and a bonding face of the cover with a step being provided. The positioning of the housing and the cover is determined, and the first target weld portions are welded to each other and second target weld portions are welded to each other by way of laser radiation.

A flow rate sensor includes: a housing made from a resin material and having a bottom base portion and a side wall, at least one surface side of the housing being open; a cover made from a resin material, covering the one surface side of the housing, welded to an upper surface of the side wall of the housing, and defining, with the bottom base portion and the side wall of the housing, an auxiliary passage within which a gas to be measured flows that is taken in from a main passage; and a flow rate detection unit disposed within the auxiliary passage. A protruding portion for height control is provided to one of the housing and the cover at least in a vicinity of the side wall around the flow rate detection unit so as to suppress sinking in of the cover during welding.

A flow rate sensor includes: a housing made from a resin material and having a bottom base portion and a side wall, at least one surface side of the housing being open; a cover made from a resin material, covering the one surface side of the housing, welded to an upper surface of the side wall of the housing, and defining, with the bottom base portion and the side wall of the housing, an auxiliary passage within which a gas to be measured flows that is taken in from a main passage; and a flow rate detection unit disposed within the auxiliary passage. A protruding portion for height control is provided to one of the housing and the cover at least in a vicinity of the side wall around the flow rate detection unit so as to suppress sinking in of the cover during welding.