The subject invention pertains to a suction-controllable triaxial test system and a method for studying the micro-hydro-mechanical behavior of unsaturated soils through the visualization of the in-situ evolution of three-dimensional (3D) microstructure upon triaxial loading in a ((p-u.sub.a), q, s) space. The triaxial apparatus can be small enough to be operated within a micro-focus or nano-focus X-ray CT scanner. Internal characteristics and 3D movements of soil particles and the water and air in soil pores can be visualized during in-situ controllable hydro-mechanical loading processes without disturbing the soil sample. The evolution of 3D micro-structure of unsaturated soil samples of varying matric suction can be directly related with their element-scale behavior for conducting cross-scale fundamental studies.

An apparatus for measuring mechanical properties of a downhole material, including first and second fixtures each of the fixtures containing a force application fixture to apply a stress to a specimen of the downhole material. A confining sleeve wraps around portions of the first and second fixtures to form a sealed specimen chamber defined by an inner surface of the confining sleeve and ends of the first and second fixtures nearest the specimen. Wall of a confining chamber contain the first and second fixtures, the confining sleeve and the specimen therein. The confining chamber holds a hydraulic fluid therein such that the hydraulic fluid can exert a confining pressure on the confining sleeve to maintain the seal of the specimen chamber and to maintain contact between the inner surface of the confining sleeve and the specimen when the stress is applied to the specimen. First channels pass though one or more of the walls of the confining chamber to add and remove the hydraulic fluid to and from the confining chamber. Second channels pass though one or more of the walls of the confining chamber and through one of the first and second fixtures to add and remove a pore space fluid to and from specimen chamber ports open to the specimen chamber to maintain a pore pressure at the specimen chamber ports that is equal to or less than the confining pressure while the stress is applied to the specimen. A system and method are also disclosed.

An integral tension test system for a large-tonnage basalt fiber anchor cable includes: a plurality of basalt fiber anchoring bars each comprising a basalt fiber reinforced plastic (BFRP) bundle, a steel strand, a first and a second steel casing pipes, the BFRP bundle including a plurality of BFRPs, and a grating array temperature, stress and vibration sensing optical cables bonded in the BFRP; a vibration table and a reaction frame arranged thereon, wherein the first steel casing pipe of the basalt fiber anchoring bar is located in the reaction frame, the steel strand penetrates one end of the reaction frame to be connected to a center hole jack, and the second steel casing pipe of each basalt fiber anchor cable is located outside the reaction frame to be anchored; and a data acquisition module connected to all of the grating array temperature, stress and vibration sensing optical cables.

Aspects of the technology relate to an apparatus and method for testing a material for use in a lighter-than-air craft deployable in the stratosphere. The apparatus and method may include and use a base plate and at least one ring component to attach to the base plate to secure a portion of the material. The at least one ring component has an elliptical shape including a minor radius having a first predetermined length and a major radius having a second predetermined length. The base plate receives a gas to inflate and pressurize the portion of the material. The first predetermined length and second predetermined length are selected to impart a stress ratio up to a predetermined maximum ratio onto the portion of the material through a predetermined temperature range when the portion of the material is inflated to a predetermined pressure.

An integral tension test system for a large-tonnage basalt fiber anchor cable includes: a plurality of basalt fiber anchoring bars each comprising a basalt fiber reinforced plastic (BFRP) bundle, a steel strand, a first and a second steel casing pipes, the BFRP bundle including a plurality of BFRPs, and a grating array temperature, stress and vibration sensing optical cables bonded in the BFRP; a vibration table and a reaction frame arranged thereon, wherein the first steel casing pipe of the basalt fiber anchoring bar is located in the reaction frame, the steel strand penetrates one end of the reaction frame to be connected to a center hole jack, and the second steel casing pipe of each basalt fiber anchor cable is located outside the reaction frame to be anchored; and a data acquisition module connected to all of the grating array temperature, stress and vibration sensing optical cables.

A system for causing wear to a material in representative downhole conditions is provided, and can include a housing with a chamber at least partially filled with a fluid, an abrasion device at least partially immersed in the fluid, a heat transfer element thermally coupled to a housing, an engagement arm coupled to the housing and a test sample attached to the engagement arm that can apply an engagement force to the test sample causing engagement of the test sample with the abrasion device. An actuation device can displace the abrasion device relative to the test sample, and cause wear of the test sample during a wear test in response to the engagement of the test sample with the abrasion device. A controller can control a thermal output of the heat transfer element to maintain the chamber within a temperature range that is representative of the downhole conditions.

In one aspect, an apparatus includes a chamber configured to control one or more of humidity, pressure, or temperature and a jaw configured to flex a material system. The chamber includes an enclosure disposed within the chamber, the enclosure having an insulating material, and a motor or an actuator disposed within the enclosure. The chamber includes an inlet tube coupled with the enclosure at a first end and a first wall of the chamber at a second end. In one aspect, a method for determining material performance includes exposing a material system to a relative humidity of from 0% to 98% and flexing the material system at a first temperature in a chamber, the chamber comprising an enclosure disposed within the chamber and a motor disposed within the enclosure. The method includes operating the motor at a second temperature different from the first temperature during the flexing.

A device for a low stress triaxial test includes a test platform; a pressure chamber disposed on the test platform; a base disposed on the pressure chamber and fixed to the test platform; a support disposed on the test platform; a servo motor disposed on the support; a loading piston connected to the servo motor and penetrating into the pressure chamber; an axial force sensor disposed on the loading piston; a top cap detachably connected to the loading piston and covering the sample; a first pipeline connected to the base and passing through the test platform to connect with a measurement system; a second pipeline connected to the pressure chamber and passing through the test platform to connect with a confining pressure control system; and a third pipeline connected to the first pipeline and the top cap. The device can ensure the accuracy and authenticity of test results.

A system for causing wear to a material in representative downhole conditions is provided, and can include a housing with a chamber at least partially filled with a fluid, an abrasion device at least partially immersed in the fluid, a heat transfer element thermally coupled to a housing, an engagement arm coupled to the housing and a test sample attached to the engagement arm that can apply an engagement force to the test sample causing engagement of the test sample with the abrasion device. An actuation device can displace the abrasion device relative to the test sample, and cause wear of the test sample during a wear test in response to the engagement of the test sample with the abrasion device. A controller can control a thermal output of the heat transfer element to maintain the chamber within a temperature range that is representative of the downhole conditions.

The invention discloses an experimental test method for subcritical propagation rate of rock fractures based on triaxial stress-strain curve, including: Step 1: preparing test sample core for experiment; Step 2: putting core into triaxial rock mechanics test system, applying constant radial confining pressure to core, and applying axial stress in the axial direction until the core is macroscopically damaged; recording experimental parameters of axial stress, strain and corresponding loading time of the core; Step 3: drawing stress-strain curve of the test core according to detection data points of axial stress and axial strain; Step 4: in the stress-strain curve of the test core, starting time and ending time of the subcritical propagation stage of fractures inside the core correspond to the initiation stress σci and damage stress σcd, respectively, and calculating subcritical propagation rate of the subcritical fracture propagation stage of the test core.