A tensile testing machine exerts tensile force to biological, tissue attached to a bone. A fixture 10 according to the present invention includes a holder 11, which holds a bone B, and a support 12, which supports the holder 11. The holder 11 is provided with around-bone-axis angle adjusting mechanisms 14, 15, which adjust the angle of rotation of the bone B around the bone axis of the hone B held by the holder 11. The holder 11 and the support 12 are provided with bone inclination angle adjusting mechanisms 15, 34, which adjust the inclination angle of the bone B held by the holder 11. The support 12 is provided with lateral position adjusting mechanisms 34, 35, which adjust the lateral position of the holder 11 and longitudinal position adjusting mechanisms 35, 36, which adjust the longitudinal position of the holder 11.

A tensile testing machine exerts tensile force to biological, tissue attached to a bone. A fixture 10 according to the present invention includes a holder 11, which holds a bone B, and a support 12, which supports the holder 11. The holder 11 is provided with around-bone-axis angle adjusting mechanisms 14, 15, which adjust the angle of rotation of the bone B around the bone axis of the hone B held by the holder 11. The holder 11 and the support 12 are provided with bone inclination angle adjusting mechanisms 15, 34, which adjust the inclination angle of the bone B held by the holder 11. The support 12 is provided with lateral position adjusting mechanisms 34, 35, which adjust the lateral position of the holder 11 and longitudinal position adjusting mechanisms 35, 36, which adjust the longitudinal position of the holder 11.

Methods and systems for determining a change in condition of a rock bolt. Some methods may comprise, at a first point in time, propagating shear and longitudinal ultrasonic waves along the rock bolt to measure a first time of flight for each of the shear and longitudinal waves, at a second point in time after the first point in time, propagating shear and longitudinal ultrasonic waves along the rock bolt to measure a second time of flight for each of the shear and longitudinal waves, and using the relative changes of the first and second time of flights, determining the change in condition of the rock bolt section.

Methods and systems for determining a change in condition of a rock bolt. Some methods may comprise, at a first point in time, propagating shear and longitudinal ultrasonic waves along the rock bolt to measure a first time of flight for each of the shear and longitudinal waves, at a second point in time after the first point in time, propagating shear and longitudinal ultrasonic waves along the rock bolt to measure a second time of flight for each of the shear and longitudinal waves, and using the relative changes of the first and second time of flights, determining the change in condition of the rock bolt section.

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.

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 discloses a device for testing strength and sealing performance of cement sheath after perforation, comprising a cement sheath curing maintenance simulation component, a perforation operation simulation component, and a cement sheath performance test component. By simulating the detonation effect and fluid-solid coupling effect, quantitatively testing the internal transverse crack and longitudinal crack propagation size, compressive strength and tensile strength, permeability, blowby pressure, blowby velocity and other parameters of the cement sheath, drawing the relation curve between different perforation distances and the maximum blowby pressure and permeability of the cement sheath, determining the perforation distance H.sub.p where the blowby of the cement sheath does not occur, determining the perforation distance H.sub.K to ensure the sealing of the cement sheath, and using min (H.sub.p, H.sub.K), the critical perforation distance that the cement sheath has sufficient strength to prevent blowby and meet the sealing requirements can be determined.

The invention discloses a device for testing strength and sealing performance of cement sheath after perforation, comprising a cement sheath curing maintenance simulation component, a perforation operation simulation component, and a cement sheath performance test component. By simulating the detonation effect and fluid-solid coupling effect, quantitatively testing the internal transverse crack and longitudinal crack propagation size, compressive strength and tensile strength, permeability, blowby pressure, blowby velocity and other parameters of the cement sheath, drawing the relation curve between different perforation distances and the maximum blowby pressure and permeability of the cement sheath, determining the perforation distance H.sub.p where the blowby of the cement sheath does not occur, determining the perforation distance H.sub.K to ensure the sealing of the cement sheath, and using min (H.sub.p, H.sub.K), the critical perforation distance that the cement sheath has sufficient strength to prevent blowby and meet the sealing requirements can be determined.

Methods, devices, and systems for testing the flexibility of a sample such as an electronic device are provided herein. A testing system can have a motor operably connected to a mandrel such that the motor causes the mandrel to accurately and precisely rotate and cause the sample to conform to an outer surface of the mandrel. Moreover, a proximal end of the sample is secured to the outer surface of the mandrel, and the opposing distal end is controlled by a retractable holder such that the entire sample is subjected to a constant bend radius as the mandrel rotates. Other aspects and features such as controlling the environment around the mandrel and securing small samples to the mandrel are also described herein.

Methods, devices, and systems for testing the flexibility of a sample such as an electronic device are provided herein. A testing system can have a motor operably connected to a mandrel such that the motor causes the mandrel to accurately and precisely rotate and cause the sample to conform to an outer surface of the mandrel. Moreover, a proximal end of the sample is secured to the outer surface of the mandrel, and the opposing distal end is controlled by a retractable holder such that the entire sample is subjected to a constant bend radius as the mandrel rotates. Other aspects and features such as controlling the environment around the mandrel and securing small samples to the mandrel are also described herein.