Disclosed are a test method and algorithm for an aging life of a composite, and a use thereof. The test method and algorithm includes: respectively placing specimens in four temperature environments to undergo damp and hot, high and low temperature impact and high and low temperature alternating cycle for a specified time; testing the physical, chemical and electrical properties of the specimens by using laminated combined test pieces; fitting parameters in a micro-gasification expansion oscillation equation; fitting constants in a kinetic correlation equation (2) of the parameters; calculating new values of the parameters in any temperature environment by using the constant equation (2); and substituting the new values of the parameters back into the equation (1), so as to evaluate or predict the physical, chemical and electrical properties of the specimens at any time.

Disclosed is a method for compiling an equivalent acceleration spectrum of creep under variable temperatures and loads. The method includes following steps: respectively carrying out a material high-temperature tensile test, material high-temperature creep tests and creep tests under two-stage variable temperatures and loads, and calculating values of a parameter p in a creep damage accumulation model under two-stage variable temperatures and loads; based on a nonlinear damage accumulation model under multi-stage variable temperatures and loads, calculating a damage D caused by a multi-stage variable temperatures and loads creep load spectrum by utilizing values of parameter p; based on the principle of consistency of damage D, transforming the multi-stage variable temperatures and loads creep load spectrum into an equivalent acceleration spectrum of a first-order maximum creep load, and finally compiling the equivalent acceleration spectrum of creep under variable temperatures and loads.

Disclosed is a method for compiling an equivalent acceleration spectrum of creep under variable temperatures and loads. The method includes following steps: respectively carrying out a material high-temperature tensile test, material high-temperature creep tests and creep tests under two-stage variable temperatures and loads, and calculating values of a parameter p in a creep damage accumulation model under two-stage variable temperatures and loads; based on a nonlinear damage accumulation model under multi-stage variable temperatures and loads, calculating a damage D caused by a multi-stage variable temperatures and loads creep load spectrum by utilizing values of parameter p; based on the principle of consistency of damage D, transforming the multi-stage variable temperatures and loads creep load spectrum into an equivalent acceleration spectrum of a first-order maximum creep load, and finally compiling the equivalent acceleration spectrum of creep under variable temperatures and loads.

Compositions including reclaimed asphalt may be optimized for performance that is comparable with asphalt compositions that do not contain any reclaimed asphalt. In a method to determine an optimal level of reclaimed asphalt for use with at least a rejuvenator, TSRST tests are carried out on test asphalt compositions with varying levels of reclaimed asphalt (RA) materials to obtain failure temperature and failure stress data for all compositions. The test results are compared to identify composition(s) with optimal amount of RA. The optimal asphalt composition containing the maximum amount of RA for comparable performance may have a failure temperature within±5% of the failure temperature of the reference composition, and a failure stress that may be equal to or greater than the failure stress of the reference composition.

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.

The invention relates to a design method of high-temperature nickel-based bolts based on damage tolerance theory, comprising the following steps: S.sub.1: acquiring operating parameters for the design; S.sub.2: selecting a material for bolts; S.sub.3: acquiring mechanical properties of the materials; S.sub.4: determining a pretension stress σ.sub.p of a single bolt; S.sub.5: determining the service stress σ.sub.s under the steady state; S.sub.6: determining the number n, the effective cross-section area A and the distribution of bolts; S.sub.7: determining a maximum allowable crack dimension; S.sub.8: calculating the maximum allowable service stress σ.sub.th using the crack propagation threshold K.sub.th at the design temperature; S.sub.9: comparing the service stress σ.sub.s and the maximum allowable service stress σ.sub.th, if σ.sub.s is smaller than σ.sub.th, then the bolts are safe in the design life; otherwise, return to step S.sub.4 and reduce the pretension stress σ.sub.p.

The invention relates to a design method of high-temperature nickel-based bolts based on damage tolerance theory, comprising the following steps: S.sub.1: acquiring operating parameters for the design; S.sub.2: selecting a material for bolts; S.sub.3: acquiring mechanical properties of the materials; S.sub.4: determining a pretension stress σ.sub.p of a single bolt; S.sub.5: determining the service stress σ.sub.s under the steady state; S.sub.6: determining the number n, the effective cross-section area A and the distribution of bolts; S.sub.7: determining a maximum allowable crack dimension; S.sub.8: calculating the maximum allowable service stress σ.sub.th using the crack propagation threshold K.sub.th at the design temperature; S.sub.9: comparing the service stress σ.sub.s and the maximum allowable service stress σ.sub.th, if σ.sub.s is smaller than σ.sub.th, then the bolts are safe in the design life; otherwise, return to step S.sub.4 and reduce the pretension stress σ.sub.p.

A heating system for use in mechanical testing at scales of microns or less includes a stage heater. The stage heater having a stage plane, and a stage heating element distributed across the stage plane. Two or more support mounts are on opposed sides of the stage plane. A first bridge extends from the stage plane to a first mount of the two or more support mounts, and a second bridge extends from the stage plane to a second mount of the two or more support mounts. The first and second bridges provide a plurality of supports between the stage plane and two or more support mounts to accordingly support the stage plane. In another example, the heating system includes a probe heater configured to heat a probe as part of mechanical testing.

A heating system for use in mechanical testing at scales of microns or less includes a stage heater. The stage heater having a stage plane, and a stage heating element distributed across the stage plane. Two or more support mounts are on opposed sides of the stage plane. A first bridge extends from the stage plane to a first mount of the two or more support mounts, and a second bridge extends from the stage plane to a second mount of the two or more support mounts. The first and second bridges provide a plurality of supports between the stage plane and two or more support mounts to accordingly support the stage plane. In another example, the heating system includes a probe heater configured to heat a probe as part of mechanical testing.

A system for measuring change in length and/or deformation force on a sample in a longitudinal direction. The system is useful in thermomechanical analysis and/or dynamic-mechanical analysis, and comprises a pushrod extending in the longitudinal direction which exerts force on the sample, and a device measuring movement of the pushrod resulting from the change in length or deformation of the sample in the longitudinal direction. The measuring device includes: a pushrod base mounted on a stationary base with a guide so as to be movable in the longitudinal direction; a controllable drive for moving the pushrod; a detector measuring the force exerted by the pushrod on the sample; and a path sensor for measuring the movement of the pushrod.