A stress measuring device and a stress measuring method for measuring a stress distribution of an object are provided. The stress measuring method includes: receiving a first-dimension image of the object; marking an area of the first-dimension image to generate a marked area; calculating a first stress applied to the marked area and transforming the marked area to a strained marked area corresponding to a second-dimension image to generate a determination result; and calculating the stress distribution corresponding to the first-dimension image of the object according to the determination result.

A measurement device is configured to set an observation surface on a surface of a structure as a measurement surface to measure a change of the measurement surface as a measurement surface change vector. An estimator is configured to generate an estimation model based on a shape model obtained by modeling a shape of the structure. The estimator is configured to acquire a coefficient vector by solving a norm minimization problem by setting, as parameters, a measurement surface change vector and a part of the estimation model. The coefficient vector forms a sparse solution. The estimator is configured to estimate a change of a crack occurrence surface by determining a candidate surface, which is inside the structure and assumed to have a crack, as the crack occurrence surface, based on the coefficient vector and another part of the estimation model.

A method of determining a maximum acceptable alternating stress at a point of a part subjected to cyclic loading: simulating that the part is subjected to constant loading equal to a threshold value during a level period, and assuming that the part has elasto-viscoplastic behavior; from the results of the simulation, determining a final static stress at the point at the end or after the end of the level period; and for the point under consideration, using a Goodman diagram to determine the maximum acceptable alternating stress, which is determined for a static stress equal to the final static stress; the duration of the level period being equal to the duration of the loading of the testpieces that were used to draw up the Goodman diagram.

A method for modelling and fatigue strength assessment of weld seams between mechanical parts includes providing a finite element model for an assembly, in which a first finite element mesh for a mechanical part, a second mesh for a second mechanical part, and a third mesh for a weld seam joining the mechanical parts comprising a number of notches are generated. The third mesh has fewer than 20 finite elements in cross-section, the notches are modelled sharp-edged, and the distribution of the finite elements follows a defined mesh pattern. The method includes calculating the finite element model. Result values of the finite elements and nodes are provided from the defined mesh pattern of the third mesh. The method includes applying an effective notch stress prediction algorithm matched to the defined mesh pattern to predict occurring notch stresses in the notches using the provided result values as input parameters.

A stress measuring device and a stress measuring method for measuring a stress distribution of an object are provided. The stress measuring method includes: receiving a first-dimension image of the object; marking an area of the first-dimension image to generate a marked area; calculating a first stress applied to the marked area and transforming the marked area to a strained marked area corresponding to a second-dimension image to generate a determination result; and calculating the stress distribution corresponding to the first-dimension image of the object according to the determination result.

The present disclosure relates to an information processing device, an information processing method, and a program for enabling more accurate prediction of a crack to be made. A model acquisition unit acquires a structure model M.sub.D from a model generation unit, an external device (not illustrated), or the like. Amplitude load energy A in an element E0 having no cracks is set on the basis of a relationship between an equivalent stress and an equivalent elastic strain experimentally obtained according to a material constituting the element E0. Since the equivalent elastic strain depends on a crack variable p, the amplitude load energy A is expressed as a function of the crack variable . A crack prediction unit predicts a crack to be generated in a structure D by calculating a differential equation having a term proportional to the amplitude energy. The present disclosure can be applied to, for example, a crack prediction device that predicts a crack.

An example method for identifying an internal flaw in a part produced using additive manufacturing includes calculating a proof load of a part, in which the proof load is a load that when applied to the part will cause the part to fail based on presence of an internal flaw in the part, determining whether the part can withstand the proof load based on a geometry of the part and static strength data, and based on a determination that the part can withstand the proof load, applying the proof load to the part during a compliance test of the part. The proof load causes the part to fracture, when applied to the part, based on presence of the internal flaw in the part that is of a threshold size at which the internal flaw would cause cracking and potential part failure when the part is placed under the operational load.

A method includes two or more reference strain gradient information being a relationship between the strain at the hole edge and a strain gradient along a radial direction. Hole expansion forming is performed on the evaluation metal sheet under the same forming conditions as respective forming conditions corresponding to at least two pieces of the reference strain gradient information to obtain at least two limit hole expansion ratios at a hole expansion limit of the evaluation metal sheet. A formable region of the evaluation metal sheet is obtained from the at least two pieces of the reference strain gradient information and the obtained at least two limit hole expansion ratios at the hole expansion limit. Stretch flange cracking at the sheared end face of the evaluation metal sheet is evaluated by the obtained formable region.

Due to geometric discontinuities introduced by welding and joining processes, stresses or strain cannot be calculated reliably calculated using modern analytical and computer methods as result of stress or strain singularity at joint locations, which leads to severe mesh sensitivity. Design and fatigue evaluation of these structures remain empirical. This disclosure addresses mesh insensitivity of stress/strain calculations for welded structures through a cut-plane traction stress method through a novel post processing of conventional finite element computation results, as well as provides a unified fatigue evaluation procedure for fatigue design and structural life evaluation for both low-cycle and high cycle fatigue regime subjected to either proportional or non-proportional multiaxial fatigue loading, as well as a simple and reliable method for treating spot welds.

A fracture determination device is provided which can predict fracture in an ultra-hard steel material. This fracture determination device 1 is provided with: a reference forming limit value generation unit 22 which, on the basis of reference forming limit value information, generates a reference forming limit value for a reference element size, which is the element size used as a reference; a target forming limit value generation unit 23 which uses the tensile strength of the steel material to change the reference forming limit value, predict the forming limit value for the element size and generate a target forming limit value; an analysis running unit 24 which runs a deformation analysis using input information and which outputs deformation information including the strain of each of the elements; a principal strain determination unit 25 which determines the maximum principal strain and the minimum principal strain of each of the elements included in the deformation information; and a fracture determination unit 26 which, on the basis of the determined maximum principal strain and minimum principal strain of each of the elements and the target forming limit value, determines whether each element in the analysis model will fracture.