Methods and apparatus for extracting one or more mechanical properties for a material based on one or more indentation parameters for the material. The method comprises receiving load-displacement data from one or more instrumented indentation tests on the material, determining, by at least one computer processor, the indentation parameters for the material based, at least in part, on the received load-displacement data, providing as input to a trained neural network, the indentation parameters for the material, determining, based on an output of the trained neural network, the one or more mechanical properties of the material, and displaying an indication of the determined one or more mechanical properties of the material to a user of the computer system.

The present invention discloses a method for evaluating and preventing creep damage to conductivity of hydraulic fracture in gas reservoirs, comprising: (1) selecting a rock sample of target reservoir for creep experiment, and plotting ε-t curve of the rock sample during creep; (2) fitting the fractional Kelvin model with the ε-t curve of the rock sample during creep; (3) calculating the conductivity and permeability of hydraulic fracture considering creep damage; (4) numerically solving the productivity model, calculating the cumulative gas production of the gas well produced up to time t, and calculating the creep damage rate for cumulative production of the gas well; (5) repeating Steps (3) to (4), calculating the creep damage rate for cumulative production for the cases of hydraulic fracture sanding concentration N of 5 kg/m.sup.2, 7.5 kg/m.sup.2, 10 kg/m.sup.2, 12.5 kg/m.sup.2 and 15 kg/m.sup.2 respectively, plotting the creep damage chart of cumulative production.

A method of manufacturing a mold by a machine tool, the method including predicting a thermal fatigue life of a mold which is made of a mold material having a hardness H and on which heating during contact with a workpiece and cooling after contact with a workpiece are repeated, the method including a step for obtaining a thermal stress maximum value σ.sub.h_MAX among a plurality of thermal stress values at a position x on the mold and a temperature T.sub.h at the thermal stress maximum value, wherein the temperature at the thermal stress maximum value σ.sub.h_MAX is a temperature lower than a maximum temperature among the plurality of temperatures, the machine tool manufactures the predetermined mold shape from a mold material having one of the plurality of hardnesses in which the thermal fatigue life was obtained based on the thermal stress maximum value, the yield strength, and the contraction.

A method for determining an expansion coefficient of a test material comprises: receiving first image data of a compound material, wherein the compound material comprises a plate and a layer of the test material, which is attached to the plate; receiving second image data of the compound material, which has been exposed to an environmental condition, before the second image data has been recorded; determining a measured deformation of the compound material by comparing the first image data and the second image data; and performing a simulated deformation of a model of the compound material exposed to the environmental condition and determining the expansion coefficient of the test material by varying the expansion coefficient until the simulate deformation conforms to the measured deformation.

The present disclosure relates to a method for determining initiation positions of fretting fatigue cracks. The processed inner circular hole test workpiece is placed on a stage of an optical microscope, wherein the inner hole surface to be measured is perpendicular to the scanning beam direction of the microscope; measurement is performed along the real contact orientation between the inner hole surface of the inner circular hole test workpiece and the pin shaft. From the measured surface morphology and profile image, rectangular target areas with a coverage rate of 75%˜90%, and the amplitude distribution function, surface skewness and surface kurtosis values of the respective surface profiles are extracted from the target areas. By comparing the positive/negative of and the magnitude of the skewness and kurtosis values measured in the target areas, the side where the initiation position of fretting fatigue cracks is located can be determined.

A method for predicting a creep fracture behavior of a woven ceramic matrix composite is provided. A fiber axial stress distribution equation is obtained according to a shear lag model, a random matrix cracking model, a fracture mechanical interface debonding criterion and a fiber failure model; a matrix crack spacing equation is obtained according to the random matrix cracking model; an interface debonding length equation is obtained according to the fracture mechanics interface debonding criterion, and an equation of the load bearing relationship between intact fibers and broken fibers and a fiber fracture probability equation are obtained based on an overall load bearing criterion; and at last a creep strain equation of the woven ceramic matrix composite material is obtained, according to the overall load bearing criterion, to predict the creep fracture behavior of the woven ceramic matrix composite material affected by the random load.

A method for specifying the material of glass or glass ceramic components by either the minimum service life of a component as a function of a predefined mechanical stress or the mechanical resistance as a function of a predefined service life during which mechanical stress occurs. The method enables a leaner dimensioning of mechanically stressed glass and glass ceramic components.

The present disclosure provides a method for inversion of crystal plasticity material parameters based on nanoindentation experiments. The method comprises: firstly, obtaining the elastic modulus of material by Oliver-Pharr method; secondly, establishing a macroscopic parameter inversion model of nanoindentation, correcting actual nanoindentation experimental data by pile-up/sink-in parameters and calculating macroscopic constitutive parameters of indentation material in combination with a Kriging surrogate model and a genetic algorithm; and finally, establishing a polycrystalline finite element model for a tensile specimen based on crystal plasticity finite element method, and calculating the crystal plasticity material parameters according to the calculated constitutive parameters of the material in combination with the Kriging surrogate model and the genetic algorithm. Compared with the prior art, the present disclosure can improve the calculation accuracy, reduce the amount of calculation and enhance calculation convergence, and has both practical and guideline values for the inversion of crystal plasticity material parameters.

A method for estimating life of a component includes obtaining fracture data corresponding to a component. The fracture data includes a first dataset corresponding to a threshold region where the crack in the component is dormant below a fatigue threshold. The method further includes determining initial estimates of parameters of a crack growth rate model and parameters of temperature models corresponding to the crack growth rate model based on the fracture data. The method also includes computing optimized parameters of temperature models corresponding to the crack growth rate model, and a scatter parameter via simulation of a joint optimization method using the initial estimates. The method includes determining a cumulative distribution function based on the optimized parameters and the scatter parameter and estimating life of the component based on the cumulative distribution function.

There is provided a method for estimating a hardness of a cold worked component including: preparing a test piece for hardness measurement having a dent portion of a shape corresponding to a shape of the contact surface of the punch by using a mounting base on which a test piece is mounted and a punch of which a contact surface to be in contact with the test piece is a curved surface, and compressing the test piece mounted on the mounting base using the punch; measuring hardnesses of the test piece for hardness measurement at a plurality of hardness measurement positions in a measurement direction while taking, as the measurement direction, a direction in the dent portion in which a sheet thickness changes; performing numerical analysis to calculate equivalent plastic strains of the test piece for hardness measurement, and acquiring a hardness-equivalent plastic strain curve on the basis of the hardnesses and the equivalent plastic strains at the hardness measurement positions; and specifying a hardness from the calculated value of equivalent plastic strain of an arbitrary part of the cold worked component on the basis of the hardness-equivalent plastic strain curve by performing numerical analysis to calculate a value of equivalent plastic strain of a cold worked component.