33 results about "Hydrostatic stress" patented technology

The present invention relates to a float collar apparatus for regulating the passage of fluid through a casing liner or sub-sea casing. Apparatus of the present invention is fabricated using plastic flapper valves and sleeve components in contrast to prior art float collar components which are fabricated almost entirely of hard metals. The use of plastic components in the float collar apparatus of the present invention provides a substantial reduction in time and resources expended during drilling out of the float collar once cementing operations are completed. Additionally, the float collar apparatus of the present invention is fabricated from a pre-determined combination of plastic components and metal components thereby ensuring that the improved float collar can still endure substantial hydrostatic stresses encountered during casing liner running in and cementing operations.

A vibration isolation structure is provided with a stress reduction section that can reduce the hydrostatic stress from tensional load along a stacking direction of portions of a composite laminated member corresponding to a first end side and a second end side in a shear direction orthogonal to the stacking direction to lower than the hydrostatic stress from tensional load along the stacking direction of other portions of the composite laminated member.

The invention discloses a method for predicting sheet forming fractures based on a damage fracture standard numerical value. The method includes the steps of obtaining the stress state distribution of a metal sheet cylindrical piece in the stamping process according to the thermodynamics irreversible law, obtaining a stress balance differential equation of the metal sheet cylindrical piece in the stamping process according to the stress state distribution, calculating the change rate, occurring when the metal sheet cylindrical piece is damaged, of the area of a small unit of the metal sheet cylindrical piece in the stamping process according to the continuum damage mechanics theory, obtaining the damage to the metal sheet cylindrical piece according to the change rate, calculating the relation between the damage and the strain of the metal sheet cylindrical piece, and finally deriving the relation between the damage value and the true stress, true strain and hydraulic stress of the metal sheet cylindrical piece under the unidimensional scale in the whole stamping process. By means of the method, the technical problem that when fractures during sheet forming are predicted through an existing numerical value method, errors are large can be solved.

A method is given for fracturing a formation, in particular far-field in a tight formation, in which at least a portion of the proppant is crushable in situ at some point during pumping, during fracture closure, or at higher stresses experienced later during fracture closure. The closure stress or hydrostatic stress is estimated, then a proppant is selected that is at least partially crushable at that closure stress, and then the fracturing treatment is performed with at least a portion of the total proppant being the selected crushable proppant.

A system and method measuring subterranean stress. The system and method includes a non-destructive sheath enveloping a tubular structure positioned in direct contact with a lateral subterranean rock formation for sensing expansive changes in the subterranean rock formation. A fiber optic is directly embedded in the non-destructive sheath positioned adjacent to the exterior surface of the tubular structure. The fiber optic transmits light and thereafter receives light in proportion to the expansive changes in the subterranean rock formation. A spectrometer connected to the fiber optic remote from the non-destructive sheath. The spectrometer measures hydrostatic stress in the subterranean rock formation without estimating acoustoelastic effects or occluding the tubular structure.

The present invention proposes a titanium alloy fine-blanking forming method. For TC4 titanium alloys of different thicknesses, fine-blanking is carried out by using finite element and experimental methods to obtain blank holder force, anti-deterministic force and stamping speed. The influence relationship of the hydrostatic pressure stress in the cutting strip, and then use the fracture criterion to judge the cracks under the hydrostatic pressure stress. Through a large number of experiments and simulation data fitting, the blank holder force and anti-bracket force obtained in the patent are obtained. The design relationship curve of force and blanking speed can be used to obtain the optimal combination of blank holder force, reverse jacking force and blanking speed, that is, the blank holder force and reverse jacking force increase continuously with the fine blanking process. , the punching speed is continuously reduced, so that the material in the shear zone is always in a good hydrostatic stress state, and a good shear bright zone is obtained. The invention realizes the fine blanking forming of the titanium alloy material, has high production efficiency, high utilization rate of raw materials, and good surface quality of formed parts.

The disclosed method of making a length of pipe can produce a fatigue resistant length of pipe having a relatively high fatigue resistance and a relatively small strip-to-strip weld length. Fatigue resistance is calculated from an experimental setup with control parameters and / or a simulation replicating similar material properties and loading conditions. High fatigue resistance means that certain product characteristics, such as low plasticity, low hydrostatic stress levels and defect-free welds, can be maintained after a specific number of tested cyclic loadings with adequate weld offset design at low values. The relatively small strip-to-strip weld length reduces the likelihood of crack initiation and / or propagation at weld locations where defects and local differences in mechanical properties often cause failure. Small strip-to-strip weld lengths can also reduce weld costs.

The invention discloses a plastifying fine blanking formation technology design method based on crack initiation control. The method comprises the following steps that according to the fracture criterion of fine blanked materials, critical hydrostatic stress during crack initiation of plates is obtained; in the fine blanking process, edge pressing force, blanking force and counter ejection force are exerted on an edge pressing ring, a male die and a counter ejection plate, and the counter ejection force is increased along with increase of the blanking stroke; when the blanking stroke initial position 0 travels to the blanking stroke position S1, the edge pressing force is increased gradually, when the blanking stroke position S1 travels to the blanking stroke, in the finishing process, theedge pressing force is reduced gradually, and when the blanking stroke reaches the stroke position S1, the plates reach the critical hydrostatic stress. According to the method, the effect of restraining crack initiation is restrained, fine blanked parts with full euphotic belts are obtained, thus energy consumption in the fine blanking process is reduced, the forming quality of the parts is improved, the service life of the die is prolonged, and the good comprehensive economic benefits are obtained.