A crushing system for large-size natural gas hydrate rock samples, which mainly includes a crushing and stirring control subsystem, crushing and stirring execution subsystem and hydrate preparation subsystem. Full automatic control to parameter acquisition and experimental process is achieved by utilizing modern automation technology, including the function of automatically crushing the large-size natural gas hydrate rock samples and also monitoring, collecting and storing the drilling pressure, the torque and the internal furnace pressure and temperature parameters during the crushing process in real time, to provide reliable guarantee for the follow-up researches on crushing mechanism, crushing efficiency, drilling parameter optimization, rock crushing ability evaluation of a crushing tool and the like of the large-size natural gas hydrate rock samples and necessary experimental verification means for optimization of on-site exploiting construction conditions of natural gas hydrate.

A method of determining a minimum wall thickness for a pipe joint for use in a subsea pipeline comprises the steps of: i) determining an internal diameter of the pipe joint; ii) determining a minimum allowable hydrostatic pressure at the depth at which the pipe joint is to be used; iii) determining a target wall thickness for the pipe joint, the target wall thickness corresponding to the internal diameter and the minimum allowable hydrostatic pressure; iv) manufacturing a plurality of preliminary pipe joints having the internal diameter and the target wall thickness; v) carrying out external pressure collapse tests resulting in data representative of the hydrostatic collapse pressures at which the plurality of preliminary pipe joints collapse; vi) determining a probability distribution corresponding to the data based on a statistical tail model derived from Extreme Value Theory; vii) determining from the probability distribution a hydrostatic collapse pressure occurring with a probability of 10.sup.−5 or lower; and, viii) determining a wall thickness of the pipe joint corresponding to the internal diameter and the hydrostatic collapse pressure.

A dynamic crack leaking stoppage evaluation experiment device includes a crack simulation experiment instrument having a dynamic crack simulation mechanism. The dynamic crack leaking stoppage evaluation experiment device can simulate a dynamic change process of a crack from a closed state to an open state. An experiment method can be applied to study a variation range of the width of the crack that have been subjected to self-adaptive leaking stoppage with various combinations of leaking stoppage materials and under different increments, and the method can also be applied to quantitatively study on effecting patterns of rheological parameters and hydraulic parameters of well drilling fluid on stability of a leaking stoppage layer in the dynamic crack, so that enabled is not only simulation of leaking stoppage process of a dynamic crack, but also real-time monitoring and evaluation on leaking stoppage effect and leaking stoppage location inside the dynamic crack.

Provided is a tensile testing machine that includes a testing machine main body having a hydraulic actuator, the tensile testing machine including an estimation unit that estimates a response characteristic of the tensile testing machine, in which the estimation unit obtains the response characteristic of the testing machine main body in a state in which a first set value used for a tensile test performed by the tensile testing machine is set as a control parameter specifying operation of the hydraulic actuator, and estimates, based on the obtained response characteristic of the testing machine main body, the response characteristic of the tensile testing machine in a state in which a second set value different from the first set value is set as the control parameter.

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.

A method includes preparing a rocklike core sample for compressive testing, the rocklike core sample defining a longitudinal axis and having first and second axial ends. Preparing the rocklike core sample includes providing a throughhole in the rocklike core sample, the throughhole extending between a first opening at the first axial end and a second opening at the second axial end, wherein the first opening and the second opening are dimensioned differently. The rocklike core sample is mounted in a compressive testing apparatus, and a compressive test is performed on the rocklike core sample in the compressive testing apparatus. The compressive test includes compression in axial and radial directions. A related system includes a compressive testing apparatus and a sample preparation apparatus which prepares a rocklike core sample for compressive testing in the compressive testing apparatus, via providing a throughhole in the rocklike core sample.

Apparatus and methods related to low cycle fatigue testing are described. For example, some embodiments may contain a control box, two fitting connections, a pressure gauge, a plurality of clamps, a plurality of hydraulic cylinders, a plurality of control cables, and a strain gauge, for testing the low cycle fatigue properties of a testing specimen, for example, a steel tube umbilical.

The present invention discloses a deformation controllable compression ring-based mechanical test system for rocks with variable stiffness and a test method thereof, which comprises a loading device, a variable stiffness regulating device, a data monitoring system and a controlling system; the energy storing spring in the loading device allows the rebounding direction of the loading device to be contrary to the strain direction of the test-piece, which eliminates the energy supplement of the loading device to the test-piece and realizes the loading of an oversized stiffness on the test system; the variable stiffness regulating device precisely regulates the loaded stiffness by regulating the loaded stiffness of the test system according to test requirements, which realizes the test of loading different stiffness on the same test system and avoids the influences of differences to loading parameters between different test systems on the test results.

The invention discloses a slope one-way loading rutting test device, wherein the upper part of a loading frame is slidably connected with an upper cross beam of a frame through a loading frame rotating assembly, and a variable speed motor and a runner wheel are embedded in the lower part of the loading frame. The variable speed motor is in transmission connection with the runner wheel to realize one-way continuous loading of the runner wheel on a test piece. The lower part of a bearing frame is slidably connected with a lower cross beam of a frame through a bearing frame rotating assembly, a test piece mounting frame and a height adjusting device are sequentially embedded into the upper part of the bearing frame from top to bottom, and the height of the test piece mounting frame is adjusted through the height adjusting device.

An integrated style shear apparatus for rock structural plane comprises a frame system, a vertical loading system, a horizontal loading system, and a shearing system. Both the vertical loading system and the horizontal loading system are fixed on, and the shearing system is installed inside the frame system. The shearing system is used to prepare the sample of structural plane and actualize the shear test, the vertical loading system and the horizontal loading system are used to provide normal stress and shear stress for the shearing system respectively. The present invention also provides an experimental method by using the integrated style shear apparatus for rock structural plane, and steps of the method including: sample placement, sample adjustment, sample preparation, sample loading, instrument hookup, exerting normal stress, exerting horizontal stress, measurement and description of shear area, repeating experiment, and normal stress and shear stress calculation. The present invention can effectively reduce sample preparation error and experimental error, and can rapidly and accurately determine shear strength and deformation parameters of rock structural plane.