摘要:
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). Vertices (VI) are present on the perimeter segment including the at least four sides, respectively between the vertex (C) with the smallest inside angle among the at least three vertices (V(i)) and one (A) of the two vertices (A, B), and between the vertex (C) with the smallest inside angle and the other (B) of the two vertices (A, B), said vertices (VI) having inside angles larger than the inside angle of the vertex (C) with the smallest inside angle.
摘要:
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). Vertices (VI) are present on the perimeter segment including the at least four sides, respectively between the vertex (C) with the smallest inside angle among the at least three vertices (V(i)) and one (A) of the two vertices (A, B), and between the vertex (C) with the smallest inside angle and the other (B) of the two vertices (A, B), said vertices (VI) having inside angles larger than the inside angle of the vertex (C) with the smallest inside angle.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
Disclosed is a press forming method press forming a workpiece between a die and a punch, while pushing the punch into the die by means of a relative motion of the die and the punch, the method includes: producing an intermediate molding (100B) having ridges (100d) formed in predetermined parts of the workpiece, and then press forming the intermediate molding (100B) into a final shape, to thereby substantially thicken and work-harden the predetermined parts of the workpiece.
摘要:
Disclosed is a press forming method press forming a workpiece between a die and a punch, while pushing the punch into the die by means of a relative motion of the die and the punch, the method includes: producing an intermediate molding (100B) having ridges (100d) formed in predetermined parts of the workpiece, and then press forming the intermediate molding (100B) into a final shape, to thereby substantially thicken and work-harden the predetermined parts of the workpiece.
摘要:
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)=(σ2, σ1) (maximum principal stress: σ1, minimum principal stress: σ2) 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=(σ1/σ2)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.
摘要:
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.