Abstract: What is provided is an automobile body in which batteries, tires, and liquids containing water and oil are removed from a public road vehicle with superior collision safety, the public road vehicle comprising at least a steel material containing a steel sheet with a tensile strength of 1180 MPa or higher, a non-ferrous metal material, and a resin material, wherein the ratio of a mass mh (kg) of the steel sheet having a tensile strength of 1180 MPa or higher to a mass m (kg) of the automobile body is 9% or higher, and a mass m (kg) of the automobile body and a projected area s (m2) of the automobile body from an upper side satisfy a formula (1) and a formula (2) 6 < s < 11 ( 1 ) m < ( 2 ? 7 ? 2 . 3 ? 7 × s - 8 ? 3 ? 5 ) × 0 ? .98 .

Abstract: Provided is a frame member formed by hot-stamping a steel sheet. The frame member has a closed cross section portion in which a cross section perpendicular to a longitudinal direction is a closed cross section, and the closed cross section portion has at least one flat part having a radius of curvature larger than a maximum external dimension of the cross section. A Vickers hardness of a thickness middle portion in a reference flat part is 300 Hv or greater, a width of the reference flat part is 2.0 times or less the effective width, and a standard deviation ratio obtained by dividing a standard deviation of hardness frequency distribution in a surface layer portion in the reference flat part by a standard deviation of hardness frequency distribution in the thickness middle portion in the reference flat part is less than 1.0.

Abstract: Provided is a frame member formed by cold-pressing a steel sheet. The frame member has a closed cross section portion in which a cross section perpendicular to a longitudinal direction is a closed cross section, and the closed cross section portion has at least one flat part having a radius of curvature larger than a maximum external dimension of the cross section. A Vickers hardness of a thickness middle portion in a reference flat part is 300 Hv or greater, a width of the reference flat part is 2.0 times or less the effective width, and a standard deviation ratio obtained by dividing a standard deviation of hardness frequency distribution in a surface layer portion in the reference flat part by a standard deviation of hardness frequency distribution in the thickness middle portion in the reference flat part is greater than 1.0.

Abstract: A curved panel part includes: a curved panel made of metal; and a reinforcement joined to the curved panel and made of a plurality of FRP layers including continuous fibers, in which each of the plurality of FRP layers has a single fiber direction, at least one layer out of the plurality of FRP layers has a fiber direction different from that of another layer, in the plurality of FRP layers, a proportion of layers having an angular difference in the fiber direction of 30° or more is 15% or more of all of the layers, and when calculating, by defining a maximum principal curvature direction of the curved panel as a 0° direction and a direction orthogonal to the 0° direction as a 90° direction, each of a 0° direction component and a 90° direction component regarding the fiber direction of each FRP layer of the reinforcement joined to the curved panel, by using a trigonometric function, an expression (1) is satisfied.

Abstract: Provided is a frame member obtained by joining a first steel sheet member and a second steel sheet member at a spot-welding portion by spot welding. A cross-sectional region in which a cross section perpendicular to a longitudinal direction of the frame member is a closed cross section is formed, the first steel sheet member has a tensile strength of 1,900 MPa or more, and the spot-welding portion has a molten metal portion formed by the spot welding and a heat-affected portion adjacent to an outside of the molten metal portion. Average Vickers hardness HvAve at a measurement position corresponding to the first region on the virtual straight line and minimum Vickers hardness HvMin at a measurement position corresponding to the third region on the virtual straight line satisfy HvAve?HvMin?100.

Abstract: A panel structure includes: a panel made of metal; and a reinforcement joined to the panel and made of a plurality of FRP layers including continuous fibers, in which each of the plurality of FRP layers has a single fiber direction, at least one layer out of the plurality of FRP layers has a fiber direction different from that of another layer, in the plurality of FRP layers, a proportion of layers having an angular difference in the fiber direction of 30° or more is 15% or more of all of the layers, and when calculating, by defining a long side direction being a long direction of a long edge of the panel as a 90° direction and a direction orthogonal to the 90° direction as a 0° direction, each of a 90° direction component and a 0° direction component regarding the fiber direction of each FRP layer of the reinforcement joined to the panel, by using a trigonometric function, an expression (1) is satisfied.

Abstract: A curved panel part includes: a curved panel made of metal; and a reinforcement joined to the curved panel and made of a plurality of FRP layers including continuous fibers, in which each of the plurality of FRP layers has a single fiber direction, at least one layer out of the plurality of FRP layers has a fiber direction different from that of another layer, in the plurality of FRP layers, a proportion of layers having an angular difference in the fiber direction of 30° or more is 15% or more of all of the layers, and when calculating, by defining a maximum principal curvature direction of the curved panel as a 0° direction and a direction orthogonal to the 0° direction as a 90° direction, each of a 0° direction component and a 90° direction component regarding the fiber direction of each FRP layer of the reinforcement joined to the curved panel, by using a trigonometric function, an expression (1) is satisfied.

Abstract: A structural member for vehicle 1 includes: a hollow member 10 made of metal, the hollow member 10 including cutout forming portions 12 arranged along a member longitudinal direction of the hollow member, the cutout forming portions 12 each having a cutout 13; and reinforcing parts 20 made of FRP, the reinforcing parts 20 bonded to the hollow member 10, the reinforcing parts 20 covering each of the cutouts 13 in each of the cutout forming portions 12, in which a first cutout forming portion 12a having the cutout 13 in the first region R1 and a second cutout forming portion 12b having the cutout 13 in the second region R2 are arranged alternately along the member longitudinal direction of the hollow member 10.

Abstract: A panel structure includes: a panel made of metal; and a reinforcement joined to the panel and made of a plurality of FRP layers including continuous fibers, in which each of the plurality of FRP layers has a single fiber direction, at least one layer out of the plurality of FRP layers has a fiber direction different from that of another layer, in the plurality of FRP layers, a proportion of layers having an angular difference in the fiber direction of 30° or more is 15% or more of all of the layers, and when calculating, by defining a long side direction being a long direction of a long edge of the panel as a 90° direction and a direction orthogonal to the 90° direction as a 0° direction, each of a 90° direction component and a 0° direction component regarding the fiber direction of each FRP layer of the reinforcement joined to the panel, by using a trigonometric function, an expression (1) is satisfied.

Abstract: A structural member for vehicle 1 includes: a hollow member 10 made of metal, the hollow member 10 including cutout forming portions 12 arranged along a member longitudinal direction of the hollow member, the cutout forming portions 12 each having a cutout 13; and reinforcing parts 20 made of FRP, the reinforcing parts 20 bonded to the hollow member 10, the reinforcing parts 20 covering each of the cutouts 13 in each of the cutout forming portions 12, in which a first cutout forming portion 12a having the cutout 13 in the first region R1 and a second cutout forming portion 12b having the cutout 13 in the second region R2 are arranged alternately along the member longitudinal direction of the hollow member 10.

Abstract: A break prediction method according to the present invention predicts a break of a joint portion of an object to be analyzed including a pair of members joined to each other by using a finite element method, and includes a first step of acquiring at least an element size of a base material portion, from among parameters set in an element model for the object to be analyzed; a second step of calculating, as a break discernment standard, a break limit moment defined by a function including the element size of the base material portion as a variable; and a third step of discerning whether the moment applied to the joint portion in a deformation analysis of the element model for the object to be analyzed exceeds the break limit moment, and outputting the result of the discernment as a break prediction result for the joint portion.

Abstract: In a deformation simulation of a member joined by spot welding, an effective width being a width in a direction intersecting a direction of a load centered on a spot welded portion (14) on a flange face (13a) where the spot welded portion (14) is provided of a member (10) and changing correspondingly to a change in the load is calculated every predetermined time interval, and fracture of the spot welded portion (14) is predicted using the calculated effective width. This configuration enables precise fracture prediction of a spot welded portion where spot welding is modeled, for example, in a case of performing collision deformation prediction of an automobile member on a computer.

Abstract: This fracture determination device 1 is provided with: an element extraction unit 22 which extracts elements included in the heat affected zone formed around a spot weld in a steel material; a reference forming limit value generation unit 23 which generates a reference forming limit value depending on sheet thickness and material property of the heat affected zone on the basis of reference forming limit value information; a heat affected zone forming limit value generation unit 24 which uses the tensile strength of the steel material and element size to change the reference forming limit value, predict the forming limit value for the element size and generated a forming limit value in the heat affected zone; an analysis running unit 25 which runs a deformation SIM using input information and which outputs deformation information including maximum principal strain and minimum principal strain of each of the elements; a principal strain determination unit 26 which determines the maximum principal strain and the

Abstract: A joint provided with a base part 12, a pair of side parts 14, 14 extending from the two end parts of the base part 12 in the first direction D1 to the same side in the second direction D2 vertical to the first direction D1, the pair of side parts 14, 14 being formed with fastening holes 14H at the center in a third direction D3 vertical to both the first direction D1 and second direction D2, and a closed part 16 formed between the pair of side parts 14, 14 as an extended region of the base part 12 and pair of side parts 14, 14 at least at one end in the third direction D3.

Abstract: A fracture determination device is provided which can predict fracture in an ultra-hard steel material.

Abstract: In a deformation simulation of a member joined by spot welding, an effective width being a width in a direction intersecting a direction of a load centered on a spot welded portion (14) on a flange face (13a) where the spot welded portion (14) is provided of a member (10) and changing correspondingly to a change in the load is calculated every predetermined time interval, and fracture of the spot welded portion (14) is predicted using the calculated effective width. This configuration enables precise fracture prediction of a spot welded portion where spot welding is modeled, for example, in a case of performing collision deformation prediction of an automobile member on a computer.

Abstract: A break prediction method according to the present invention predicts a break of a joint portion of an object to be analyzed including a pair of members joined to each other by using a finite element method, and includes a first step of acquiring at least an element size of a base material portion, from among parameters set in an element model for the object to be analyzed; a second step of calculating, as a break discernment standard, a break limit moment defined by a function including the element size of the base material portion as a variable; and a third step of discerning whether the moment applied to the joint portion in a deformation analysis of the element model for the object to be analyzed exceeds the break limit moment, and outputting the result of the discernment as a break prediction result for the joint portion.

Abstract: A joint realizing higher rigidity without increasing the wall thickness provided with a base part 12, a pair of side parts 14, 14 extending from the two end parts of the base part 12 in the first direction D1 to the same side in the second direction D2 vertical to the first direction D1, the pair of side parts 14, 14 being formed with fastening holes 14H at the center in a third direction D3 vertical to both the first direction D1 and second direction D2, and a closed part 16 formed between the pair of side parts 14, 14 as an extended region of the base part 12 and pair of side parts 14, 14 at least at one end in the third direction D3.

Abstract: This DR steel sheet includes the following steel components: C: 0.02 to 0.06 mass %, Si: equal to or less than 0.03 mass %, Mn: 0.05 to 0.5 mass %, P: equal to or less than 0.02 mass %, S: equal to or less than 0.02 mass %, Al: 0.02 to 0.10 mass %, and N: 0.008 to 0.015 mass %. The amount of solute N (Ntotal?NasAlN) in the steel sheet containing a residual iron and inevitable impurities, is equal to or more than 0.006%; and the total stretchability in a rolling direction after aging is equal to or more than 10%, total stretchability in a sheet width direction after aging is equal to or more than 5%, and an average Lankford value after aging is equal to or less than 1.0.