A method of evaluating a hot stamped part manufactured by hot stamping a coated steel sheet having a Zn—Ni coating layer on a surface of a base steel sheet includes an analysis model setting step, a forming condition setting step, a forming analysis step, and an evaluation step which are performed using a computer, wherein in the evaluation step, a maximum micro-crack depth in the hot stamped part manufactured under a forming condition set in the forming condition setting step is evaluated using a correlation, obtained beforehand, between an equivalent plastic strain in a surface layer of the hot stamped part and the maximum micro-crack depth in the hot stamped part.

Systems and methods for determining mechanical properties of formation rock using, for example, millimeter-scale test samples of the formation rock are disclosed. The test samples may be single edge notched beam (SENB) test samples. The systems and methods may include performing laboratory testing on the SENB test samples and recording laboratory testing data obtained from the laboratory testing and performing a simulation on a numerical model of the SENB test samples and recording the simulation data obtained from the simulation. The laboratory testing data and the simulation data may be compared, and a determination may be made as to whether a selected degree of correlation is present between the laboratory testing data and the simulation exists. Mechanical properties of the formation rock are obtained from the simulation data when the selected degree of correlation exists between the laboratory testing data and the simulation data.

The invention features a method for determining the worn shape of a deformable body in sliding contact with a deformable substrate. A wear depth w in an inward normal direction is determined at select points on a surface of the deformable body at each point in time t by integration of the following equation:

[00001]$\frac{\mathrm{dw}}{d.Math..Math.\tau }={\mathrm{kT}}_n.Math.v^b$

where k is a material dependent variable determined by physical tests, T.sub.n is a contact pressure determined by finite element analysis of the deformable body in sliding contact with the deformable substrate at each point in time t, v is a constant sliding velocity between the deformable body and the deformable substrate, b is a constant determined by physical tests, and τ=t.sup.b is a computational time.

A system for determining parameters of porous media or material, which in an embodiment is biological tissue, includes an actuator and a displacement monitor. The actuator is adapted to apply a displacement to tissue at a particular frequency selected from a range of frequencies, and the force monitor adapted to monitor a mechanical response of tissue. The system also has a processor coupled to drive the actuator and to read the mechanical response, the processor coupled to execute from memory a poroelastic model of mechanical properties of the material, and a convergence procedure for determining parameters for the poroelastic model such that the model predicts mechanical response of the tissue to within limits.

An aspect of the present disclosure is to precisely define a constant value used in the Monkman-Grant analysis, when estimating remaining life of a high-chromium steel pipe through which high-temperature and high-pressure fluid is allowed to flow. A remaining life estimation method according to the present disclosure is particularly characterized in that a step of obtaining a constant on an accelerated creep test is performed in which a constant indicative of the product of a strain rate and a rupture time in the Monkman-Grant analysis is obtained by multiplying a first coefficient to transform uniaxial rupture ductility into multiaxial rupture ductility, the uniaxial rupture ductility being obtained from a specimen of the high-chromium steel pipe, a second coefficient to amend consumed life of the specimen, and a third coefficient to amend a measured pressure into an assessment pressure.

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, apparatus, system, and computer program product for estimating material properties. Training data comprising results of testing samples for a set of materials over a range of loads applied to the samples is identified by a computer system. A machine learning model is trained by the computer system to output the material properties for materials in structures using the training data.

Provided is a material testing machine (1) including: a load mechanism (12) that applies a load to a test object; a load measurement device that measures the load applied to the test object; and a control device (30) that performs a feedback control for the load mechanism (12) based on a deviation between a measurement value of the load and a target value of the load, in which a change in a physical quantity generated in the test object due to the load is measured, and the control device (30) includes a hunting detection unit (66) that detects hunting by comparing a frequency spectrum obtained by converting time-series data of the measurement value with a frequency spectrum obtained by converting the time-series data of the target value.

Disclosed is an equivalent acceleration method of creep loads based on a consistent failure mode. The equivalent acceleration method includes obtaining corresponding tensile strengths; obtaining corresponding creep rupture time; establishing rupture time law, minimum creep rate law and rupture strain law; calculating the value of parameter p in creep damage accumulation model; and dividing the failure mode consistency interval of creep load under variable temperature and variable load. The damage caused by the creep load in the failure mode consistency interval is calculated by using the multi-grade variable temperature and variable load creep nonlinear damage accumulation model, the damage is accelerated to the maximum creep load state in the failure mode consistency interval according to the principle of damage equivalence, and finally the equivalent acceleration of creep load is realized.

A calibration method for brittle fracture assessment parameters for pressure vessel materials based on the Beremin model includes selecting at least two types of specimens of different constraints, and calculating the fracture toughness values K.sub.0 corresponding to 63.2% failure probability for each type of specimens at a same calibration temperature by using the respective fracture toughness data. The method proceeds by obtaining the stress-strain curve of the material at the calibration temperature, generating finite element models for each type of specimens, and calculating the maximum principal stress and element volume of every element at K=K.sub.0 in each model. A series of values of m are assumed to compute a group of σ.sub.u values for each type of specimens, and then m˜σ.sub.u curves are plotted for each type of specimens. Brittle fracture assessment parameters are then determined for the material according to the coordinates of the intersection of the m˜σ.sub.u curves.