Abstract: A lower vehicle-body structure of a vehicle may include: a floor panel; a side sill; and a frame member that extends in the front-rear direction on the vehicle-width-direction inner side of the side sill and includes a front-rear extended portion that is in abutment against the side sill on the vehicle-width-direction inner side and extends in the vehicle front-rear direction along the side sill. The front-rear extended portion may include: a bottom face portion; an inner wall portion; and an inner-side flange that extends to the vehicle-width-direction inner side from a distal end portion of the inner wall portion and is joined to the floor panel. Deformation facilitating facilitators that facilitate deformation of the bottom face portion in the vehicle width direction when a collision load in the vehicle width direction is input may be formed in the bottom face portion.

Abstract: A floor tunnel protruding upwardly and extending in a vehicle longitudinal direction at a central position, in a vehicle width direction, of a floor panel, a cross member having ridgelines extending in the vehicle width direction at a rear end of the floor tunnel and a closed-cross section portion interconnecting a pair of right-and-left side sills, and a pair of right-and-left battery units positioned below the floor panel and between the side sills and provided on right-and-left sides, in the vehicle width direction, of the floor tunnel are provided. The cross member is provided with a reinforcement portion to reinforce the ridgelines in a range, in the vehicle width direction, which includes at least the position of the battery units and excludes the central position, in the vehicle width direction, of the floor panel.

Abstract: A lower vehicle-body structure of a vehicle may include: a floor panel; a side sill; and a frame member that extends in the front-rear direction on the vehicle-width-direction inner side of the side sill and includes a front-rear extended portion that is in abutment against the side sill on the vehicle-width-direction inner side and extends in the vehicle front-rear direction along the side sill. The front-rear extended portion may include: a bottom face portion; an inner wall portion; and an inner-side flange that extends to the vehicle-width-direction inner side from a distal end portion of the inner wall portion and is joined to the floor panel. Deformation facilitating facilitators that facilitate deformation of the bottom face portion in the vehicle width direction when a collision load in the vehicle width direction is input may be formed in the bottom face portion.

Abstract: A vehicle-body structure that effectively distributes and transfers a side collision load in the vehicle width direction. A cross member includes a cross member top face facing a floor panel, and a cross member front face and a cross member rear face extending from respective ends in a front-rear direction of the cross member top face to the floor panel. A reinforcement member is at a side sill-side end of the cross member top face of the cross member, and a fragile portion extending in the vehicle front-rear direction is provided at a position at a side sill-side end of the cross member and overlapping the reinforcement member. The fragile portion is selected from a cutout, a bead, and a hole. The reinforcement member is a seat mounting bracket, and the fragile portion is on a vehicle-width-direction outer side of a seat mounting surface of the seat mounting bracket.

Abstract: A vehicle-body structure that effectively distributes and transfers a side collision load in the vehicle width direction. A cross member includes a cross member top face facing a floor panel, and a cross member front face and a cross member rear face extending from respective ends in a front-rear direction of the cross member top face to the floor panel. A reinforcement member is at a side sill-side end of the cross member top face of the cross member, and a fragile portion extending in the vehicle front-rear direction is provided at a position at a side sill-side end of the cross member and overlapping the reinforcement member. The fragile portion is selected from a cutout, a bead, and a hole. The reinforcement member is a seat mounting bracket, and the fragile portion is on a vehicle-width-direction outer side of a seat mounting surface of the seat mounting bracket.