Abstract: A metallic hollow columnar member with a polygonal cross-section having at least five vertices and sides extending between the vertices, is disclosed. The polygonal cross-section is divided by two vertices (A, B) with small inside angles into two perimeter segments with a perimeter comprising one or more sides, and at least one of the two perimeter segments contains at least four sides. The respective inside angles of at least three vertices (V(i)) included in the perimeter segment which includes the at least four sides are equal to or less than 180°, the distance (SS(i)) between each of the at least three vertices (V(i)) and a straight line (L) connecting the two vertices (A, B) is shorter than ½ of the distance between the two vertices (A, B), and the inside angle of the vertex (C) with the smallest inside angle among the at least three vertices (V(i)) is larger than the inside angles of the two vertices (A, B).

Abstract: A fracture determination method for determining a fracture of a metal structure includes, when a fracture determination target portion has returned from a plastic state to an elastic state, given that a stress when the portion returned to the elastic state is (x, y)=(?2, ?1) (maximum principal stress: ?1, minimum principal stress: ?2) on a (x, y) coordinate plane, performing fracture determination of the fracture determination target portion using a re-yield stress R determined by the intersection between a straight line satisfying a relation y=(?1/?2)x and an yield curve obtained from the plastic state of the fracture determination target portion. Fracture determination can be performed with high accuracy even when the fracture determination target portion has returned from a plastic state to an elastic state.

Abstract: An image reading apparatus includes a lower unit, an upper unit arranged above the lower unit and a guide arranged on an opposite side to the lower unit with respect to the upper unit. The guide relatively rotates with respect to the upper unit in a direction away from the upper unit so as to form an ejection path, between the upper unit and the guide, of a sheet-like medium conveyed between the upper unit and the lower unit. The upper unit and the guide are close to each other respectively, at positions closest to the lower unit in respective rotation ranges of relative rotation with respect to the lower unit. The rotation range of the guide is wider than that of the upper unit, in a rotation direction away from the lower unit from the positions close to each other.

Abstract: When discretizing an analysis target part into plural elements and performing analysis, sheet thickness reduction rate or maximum principal strain at an equivalent position including a same element is compared by either a manner of combining two adjacent elements after the analysis or a manner of changing an element discretization size with two types and performing the analysis, and the element where the difference is large is extracted as a fracture risk portion. With this structure, a fracture risk portion can be extracted reliably when a fracture is predicted by a finite element method.

Abstract: A fracture determination method for determining a fracture of a metal structure includes, when a fracture determination target portion has returned from a plastic state to an elastic state, given that a stress when the portion returned to the elastic state is (x, y)=(?2, ?1) (maximum principal stress: ?1, minimum principal stress: ?2) on a (x, y) coordinate plane, performing fracture determination of the fracture determination target portion using a re-yield stress R determined by the intersection between a straight line satisfying a relation y=(?1/?2)x and an yield curve obtained from the plastic state of the fracture determination target portion. Fracture determination can be performed with high accuracy even when the fracture determination target portion has returned from a plastic state to an elastic state.

Abstract: A plurality of moving-amount detecting units respectively detects a moving amount of the sheet fed by a feeding unit at a plurality of points in a width direction of the sheet. A skew detecting unit detects a skew of the sheet based on the moving amount of the sheet detected by the moving-amount detecting units.

Abstract: The present invention provides a press forming simulation method using a finite element method for a sheet metal, in which a deformation state of a pressing tool is represented with high accuracy by superimposing at least one natural mode, for the surface shape of the pressing tool, in a no-load state.

Abstract: A plurality of moving-amount detecting units respectively detects a moving amount of the sheet fed by a feeding unit at a plurality of points in a width direction of the sheet. A skew detecting unit detects a skew of the sheet based on the moving amount of the sheet detected by the moving-amount detecting units.

Abstract: An image reading apparatus includes a lower unit, an upper unit arranged above the lower unit and a guide arranged on an opposite side to the lower unit with respect to the upper unit. The guide relatively rotates with respect to the upper unit in a direction away from the upper unit so as to form an ejection path, between the upper unit and the guide, of a sheet-like medium conveyed between the upper unit and the lower unit. The upper unit and the guide are close to each other respectively, at positions closest to the lower unit in respective rotation ranges of relative rotation with respect to the lower unit. The rotation range of the guide is wider than that of the upper unit, in a rotation direction away from the lower unit from the positions close to each other.

Abstract: A forming simulation method of an elastic-plastic material, which includes: calculating an element equivalent nodal force vector from stress tensor using a finite element method for one or a plurality of finite elements of a target configuration of the elastic-plastic material; and calculating the total equivalent nodal force vector of areas by integrating the element equivalent nodal force vector for the calculated one or more finite elements over all the areas or specified areas of the elastic-plastic material.

Abstract: When discretizing an analysis target part into plural elements and performing analysis, sheet thickness reduction rate or maximum principal strain at an equivalent position including a same element is compared by either a manner of combining two adjacent elements after the analysis or a manner of changing an element discretization size with two types and performing the analysis, and the element where the difference is large is extracted as a fracture risk portion. With this structure, a fracture risk portion can be extracted reliably when a fracture is predicted by a finite element method.

Abstract: According to exemplary embodiments of the present invention, using a fracture limit stress line obtained by converting a hole expansion ratio into a stress as a criterion for a fracture, the risk of fracture in a material can be evaluated quantitatively by comparing the relationship between data obtained from a numerical analysis using a finite element method and the fracture limit stress line. Thus, when determining a fracture limit in a stretch flange portion in a thin plate in a process including one or more deformation path variations, it is possible to obtain the fracture limit curve easily and efficiently and predict the fracture with high accuracy, and the risk of fracture upon press forming or crash can be evaluated.

Abstract: A plurality of moving-amount detecting units respectively detects a moving amount of the sheet fed by a feeding unit at a plurality of points in a width direction of the sheet. A skew detecting unit detects a skew of the sheet based on the moving amount of the sheet detected by the moving-amount detecting units.