Provided is a material performance testing system under a fixed multi-field coupling effect in a hypergravity environment, including a hoisted sealed cabin, a bearing frame, a high-temperature furnace, a mechanical test device, and a buffer device. The bearing frame and the high-temperature furnace are fixedly mounted inside the hoisted sealed cabin. The bearing frame is covered on the high-temperature furnace. The buffer device is mounted at a bottom of the high-temperature furnace. Upper and lower ends of the mechanical test device are connected in a top of the bearing frame and the bottom of the high-temperature furnace. A sample is connected and mounted at an end of the mechanical test device.

A method for predicting a total minimum horizontal stress (σ.sub.h) and a total maximum horizontal stress (σ.sub.H) for an anisotropic formation may comprise: measuring Young's moduli parallel ±15° and perpendicular ±15° to a transverse isotropy plane of a horizontal core sample from the anisotropic subterranean formation; measuring Poisson's ratios parallel ±15° and perpendicular ±15° to the transverse isotropy plane of the horizontal core sample; inputting the measured Young's moduli and Poisson's ratios of the horizontal core sample into a 1-dimensional mechanical earth model (1-D MEM); and calculating, using the 1-D MEM, a predicted total minimum horizontal stress (σ.sub.h) and a predicted total maximum horizontal stress (σ.sub.H).

A method, apparatus and system for calculating stress parameters is provided. The method comprises establishing a first image pyramid according to an image of a sample before deformation, and establishing a second image pyramid corresponding to the first image pyramid according to an image of the sample after deformation; starting from a top level in the first image pyramid, iteratively calculating displacement information on each level in the first image pyramid relative to a corresponding level in the second image pyramid based on a center point of each sub-region at each level in the first image pyramid and other positions in the sub-region; calculating strain information on the sample according to displacement information on a bottom level of the first image pyramid; and calculating stress parameters of the sample based on the strain information.

An instrument and method for mechanical properties in situ testing of materials under a high temperature and complex mechanical loads are provided. The instrument includes: a support frame module used to provide a stable support and an effective vibration isolation for each functional module of the instrument; a high-frequency fatigue load applying module used to apply a high-frequency fatigue load on a tested sample; a static-dynamic mechanical load applying module used to apply a combination of static-dynamic tension/compression/bending loads on the tested sample; a high/low temperature applying module used to apply a variable temperature environment from a low temperature to a high temperature on the tested sample; and an in-situ monitoring module that may integrate a surface deformation damage measurement assembly, a three-dimensional strain measurement assembly, a microstructure measurement assembly, and an internal damage detection assembly according to a practical testing requirement.

The present disclosure relates to a traceable in-situ micro- and nano-indentation testing instrument and method under variable temperature conditions. A macro-micro switchable mechanical loading module, a nano mechanical loading module and an indentation position optical positioning module are fixed on a gantry beam, an optical imaging axis of an optical microscopic in-situ observation or alignment module and a loading axis of the nano mechanical loading module are coplanar, the optical microscopic in-situ observation or alignment module and the function switchable module are mounted on a table top of a marble pedestal, and a contact or ambient mixed variable temperature module is fixedly mounted on the function switchable module. A modular design is adopted, the micro- and nano-indentation testing instrument is used as a core, in combination with a multi-stage vacuum or ambient chamber, an indentation depth traceability calibration module and multiple sets of optical microscopic imaging assemblies.

Provided is a method for testing a melt-fabricable fluororesin injection-molded article which enables easy determination of whether or not a tested article is a defective article due to a crack or delamination. The method for testing a melt-fabricable fluororesin injection-molded article includes determining whether or not a melt-fabricable fluororesin injection-molded article is defective due to a crack or delamination based on a stress-strain curve or tensile strength-strain curve obtained by a tensile test performed on the injection-molded article.

A method for identifying prestress force in single-span or multi-span PCI girder-bridges is provided. The method includes non-destructive steps for obtaining a set of parameters of the PCI girder-bridge under investigation, and combines various analyses to identify the change of prestress force. Therefore, the losses of prestress force are tracked and predicted. The method does not cause structural damages along the PCI girder-bridge, and the cost of the identification is significantly decreased.

The invention discloses a method for analyzing the expansive stress and expansive strain of tunnel surrounding rock, including: (1) determining the surrounding rock state of the tunnel surrounding rock before expansion and the surrounding rock state after expansion; (2) according to the determined state of the surrounding rock, determining the expansive stress and expansive strain of the tunnel surrounding rock before expansion, and determining the expansive stress and expansive strain of the tunnel surrounding rock after expansion; (3) according to the surrounding rock state of the tunnel surrounding rock after expansion, the expansive deformation radius of the tunnel surrounding rock is determined, so as to determine the expansive deformation displacement of the tunnel surrounding rock. The invention introduces the expansive behavior characteristics of the tunnel surrounding rock into the analysis of the expansive stress and expansive strain of the tunnel surrounding rock of the expansive rock tunnel, which can truly reflect the changes of the expansive stress and expansive strain of the tunnel surrounding rock during the expansion process, and can realize the quantitative calculation of expansive stress and expansive strain on the state change of surrounding rock.

The invention discloses a method for obtaining the geometrical and mechanical parameters of rock samples and a holographic scanning system thereof, wherein the system includes an observation mechanism, a multi-scale penetration mechanism, a grinding mechanism, a rock sample installation mechanism arranged on a three-axis precision motion platform, and an industrial computer controlling the operation mode of each mechanism of the platform Indentation/rotary penetration test, pulse echo signal acquisition, three-dimensional surface topography reconstruction, layer by layer grinding and repeated experiments are carried out. The geometric parameters and corresponding mechanical field parameters are obtained by spatial interpolation of the three-dimensional parameter lattice accumulated by several layers of single-layer rock parameters. The holographic scanning system and method can obtain the real spatial distribution of various media in rock samples. Combined with high performance numerical calculation method, it provides a more scientific method for the analysis of rock mechanical properties, failure and instability.

A dual indentation test method according to an aspect of the present disclosure may include a first indentation step of indenting a surface of a material using a flat first indenter and a second indentations step of indenting the surface of the material indented by the first indenter using a second indenter.