Disclosed is a method for predicting creep damage and deformation evolution behavior with time, which comprises the following steps: obtaining tensile strength σ.sub.b through high-temperature tensile test; obtaining the strain curve, minimum creep rate {dot over (ε)}.sub.m and life t.sub.ƒ through creep test; obtaining the threshold stress σ.sub.th at different temperatures; establishing the relationship between the tensile strength σ.sub.b, the threshold stress σ.sub.th and the temperature T; establishing the prediction formulas of the minimum creep rate σ.sub.th and creep life σ.sub.b based on the threshold stress {dot over (ε)}.sub.m and the tensile strength t.sub.ƒ; establishing a creep damage constitutive model, including strain rate formula and damage rate formula; obtaining the evolution behavior of strain and deformation with time; obtaining the evolution behavior of damage with time.

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 disclosure provides an apparatus and method of use thereof for compressive creep testing of materials in the presence of fluids. The apparatus includes a cantilever arm connected on a first end to a cantilever pivot and including a weight holder on a second end; a first platen connected to the cantilever arm via a swivel located between the first end and the second end; a reservoir; and a second platen disposed within the reservoir and positioned to secure a sample between the first platen and the second platen when a force is applied via the weight holder and the first platen to a sample. Electrical properties of the material can be monitored and measured during the compression creep testing.

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.

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.

Provided is an integrated shape/property control method for hot power spinning of a cylindrical part based on a hot processing map. The method comprises: during the process of thermoplastic forming of a difficult-to-deform metal, performing a high-temperature mechanical property test on the metal material at a temperature and a strain rate range where dynamic recrystallization occurs; constructing, based on the power dissipation during the thermoplastic forming and a judging criterion for flow instability and on a flow stress-strain relation obtained from the high-temperature mechanical property test, power dissipation maps and flow instability maps at different strains, respectively; combining the power dissipation maps with the flow instability maps to obtain a hot processing map of the material; according to a profile of a power dissipation rate factor η and the flow instability criterion, obtaining potential dangerous forming conditions met with the flow instability criterion, and safe forming conditions under which the power dissipation rate factor η is large and the thermoplastic forming is facilitated; and finally performing hot power spinning of the cylindrical part at the temperature and strain rate that facilitates the thermoplastic forming of the material according to the hot processing map.

An experimental system for simulating creep and stick-slip dislocations of a fault in a tunnel structure includes a box structure, a supporting device and a fault dislocation loading system. A friction effect layer, a first surrounding rock layer, a tunnel structure model, a second surrounding rock layer and an overburden pressure layer are sequentially arranged in the box structure from bottom to top. The bottom of the box structure is provided with a through hole. A plate assembly is provided on the through hole, and includes a first guide plate, a second guide plate and a loading plate. Inner sides of the first guide plate and the second guide plate are respectively provided with a first slide rail and a second slide rail. The loading plate moves along the first slide rail and the second slide rail under the action of the fault dislocation loading system.

A creep strength analysis and assessment method includes comparing whether a maximum value of a local strain and a membrane strain are less than a corresponding allowable strain, and if less, determining that a component is safe; otherwise, performing the following steps: performing stress linearization on a path to obtain a local primary membrane stress P.sub.L and a local primary bending stress P.sub.b; averaging shear stress components on the path to obtain an average shear stress τ.sub.m; obtaining a strength limit S.sub.mt, a time-independent minimum stress strength value S.sub.m and a temperature- and time-dependent stress strength limit S.sub.t for a given material, a design lifetime and a design temperature; comparing whether P.sub.L, P.sub.L+P.sub.b and P.sub.L+P.sub.b/K.sub.t are less than S.sub.mt, KS.sub.m and S.sub.t; and comparing whether τ.sub.m is less than 0.6S.sub.m and 0.6S.sub.t, and if less, the component is safe, otherwise, the component is unsafe.

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 high-throughput and small size samples tension, compression, bending test system is disclosed. The system includes a computer unit, a motor and a number of the sample testing modules mounted horizontally or perpendicular to that ground on a workbench. The sample testing modules include a sample testing modules base plate fixedly attached to the workbench, and a ball screw, a displacement sensor, a moving beam, a clamp unit, a linear moving platform unit and a force value sensor arranged on the sample testing modules base plate. A number of the sample testing modules are arrange in parallel on the workbench or uniformly distributed in a circumferential direction with a point on the workbench as a circular center.