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 σ and an equivalent elastic strain ε experimentally obtained according to a material constituting the element E0. Since the equivalent elastic strain ε depends on a crack variable φ, the amplitude load energy A is expressed as a function of the crack variable φ. 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.

The present invention discloses a multiaxial creep-fatigue prediction method based on ABAQUS, which comprises: S1: establishing an ABAQUS finite element model, and defining the viscoplastic constitutive equation of the material to be tested by means of the user subroutine UMAT; S2: determining the model parameters required by the viscoplastic constitutive equation; S3: establishing the fatigue damage calculation model and creep damage calculation model of the multiaxial stress-strain state of the material to be tested; S4: establishing an ABAQUS finite element model under the multiaxial stress-strain state, and calculating the stress-strain tensor of each cycle based on the defined viscoplastic constitutive equation and the model parameters; S5: calculating the equivalent stress and equivalent plastic strain by means of the user subroutine USDFLD, and superimposing the fatigue damage and creep damage of each cycle according to the linear cumulative damage criterion to obtain the crack initiation life of the material to be tested based on the fatigue damage calculation model and creep damage calculation model in combination with the stress-strain tensor.

A method for probabilistic fatigue life prediction using nondestructive testing data considering uncertainties from nondestructive examination (NDE) data and fatigue model parameters. The method utilizes uncertainty quantification models for detection, sizing, fatigue model parameters and inputs. A probability of detection model is developed based on a log-linear model coupling an actual flaw size with a nondestructive examination (NDE) reported size. A distribution of the actual flaw size is derived for both NDE data without flaw indications and NDE data with flaw indications by using probabilistic modeling and Bayes theorem. A turbine rotor example with real world NDE inspection data is presented to demonstrate the overall methodology.

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 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.

A combined plate-beam unit analysis method considering a residual stress effect of an orthotropic plate, which is used for analyzing an orthotropic steel bridge deck welded by a top plate of a bridge deck and a trapezoidal rib, the top plate of the bridge deck is analyzed by a flat shell unit, while each sub-plate forming a trapezoidal rib is analyzed by a plate-beam unit. The welding residual stress of a top plate and a trapezoidal rib is obtained by a residual stress self-balancing condition, and the initial deformation of a top plate and left and right web plates of a trapezoidal rib is obtained by the stress-strain relationship. The combined plate-beam unit analysis method has the advantages of less freedom and high calculation accuracy, so it is especially suitable for structural analysis of the trapezoidal rib orthotropic plates.

The present invention discloses a multiaxial creep-fatigue prediction method based on ABAQUS, which comprises: S1: establishing an ABAQUS finite element model, and defining the viscoplastic constitutive equation of the material to be tested by means of the user subroutine UMAT; S2: determining the model parameters required by the viscoplastic constitutive equation; S3: establishing the fatigue damage calculation model and creep damage calculation model of the multiaxial stress-strain state of the material to be tested; S4: establishing an ABAQUS finite element model under the multiaxial stress-strain state, and calculating the stress-strain tensor of each cycle based on the defined viscoplastic constitutive equation and the model parameters; S5: calculating the equivalent stress and equivalent plastic strain by means of the user subroutine USDFLD, and superimposing the fatigue damage and creep damage of each cycle according to the linear cumulative damage criterion to obtain the crack initiation life of the material to be tested based on the fatigue damage calculation model and creep damage calculation model in combination with the stress-strain tensor.

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.

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.

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.