A method for defining a threshold stress curve utilized in fatigue and/or damage tolerance analysis, the method including conducting a direct test method on a plurality of specimens with a notch to generate raw data, the notch in each of the specimens having a notch dimension; determining a plurality of analyzed data points based upon the raw data; determining a regression line based upon the plurality of data points, the regression line including an exponential portion and a power law portion; and connecting the exponential portion and the power law portion of the regression line to form a threshold stress curve based on the regression line.

A method of testing a material sample of a type used in a wall of a structure in a standard test for in-plane fracture toughness evaluation. The method comprises obtaining a sample having a lateral length no larger than a thickness of the wall of the structure, shaping the sample to have (a) a bottom surface, (b) a profiled top surface having a central notch, (c) a first coupling feature on a first side of the central notch, and (d) a second coupling feature on a second side of the central notch, assembling a test specimen which increases the width of the sample beyond the lateral width by coupling a first lateral extension to the first coupling feature and a second lateral extension to the second coupling feature, and applying a standard fracture toughness test to the so-assembled test specimen and sample to evaluate the fracture toughness of the sample.

Drop-weight tower (110) for reproducibly initiating a crack in a material sample for fracture mechanics testing comprising a base (120) with a top surface upon which a sample holder (124) is mounted to grip a material sample, an attachment column (140) having a linear rail (142), a carriage (162) attached to the linear rail (142) and a stage (164) is attached to the carriage. The stage (164) includes a vertical rod (184) and a razor-blade holder (178). A weight is slidably mounted to the vertical rod (184). The carriage is used to adjust the height of the stage (164) relative to the material sample. A hammer (180) slides up and down the vertical rod (184) to apply consistent and reproducible force on the razor (178) that then initiates the crack in the material sample.

The present invention provides a method of surely detecting a crack in piezoelectric elements regardless of size of the crack. The method includes applying voltage to a first piezoelectric element of a pair of piezoelectric elements to cause deformation in the first piezoelectric element, forcibly deforming a second piezoelectric element of the pair of the piezoelectric elements to generate voltage from the second piezoelectric element according to the deformation of the first piezoelectric element, finding a transfer function of the pair of the piezoelectric elements based on values of the applied voltage and the generated voltage, and detecting presence or absence of a crack in the pair of the piezoelectric elements based on an objective value obtained from the found transfer function.

A method and system is disclosed for determining upper strain limits for materials, and designing devices or components based on determined strain limits.

A destructive inspection method of a vitreous silica crucible for pulling a silicon single crystal evaluates a crack state of an inner surface of the vitreous silica crucible supported by a graphite susceptor when a load is instantaneously applied to at least one point on the inner surface via an automatic center punch while pushing the tip portion of the automatic center punch against the inner surface. The destructive inspection method can inspect the vitreous silica crucible under conditions as close to the actual conditions of use as possible.

In a stress corrosion cracking evaluation method for a steam turbine, a sample having a high sensitivity is housed in a sample box of the steam turbine, and a sample breakage time is acquired. Then, based on the sample breakage time, a breakage time of the steam turbine is estimated.

A chemically strengthened glass includes a first main surface, a second main surface opposite to the first main surface, and an end surface connecting the first main surface and the second main surface. A compressive stress layer is provided in the first main surface and the second main surface. An average sheet thickness t is from 0.06 to 0.25 mm. When a bending test method is performed, a crack originating in at least one main surface of the first main surface and the second main surface is not formed.

A reinforced concrete tile having top and bottom surfaces defining a thickness, the reinforced concrete tile comprising two or more reinforcing inserts imbedded in the concrete tile in proximity to the bottom surface, the two or more reinforcing inserts being of elongated shape and comprising a plurality of scales distributed along the length and extending upwardly from the bottom surface whereby a compensating force is created upon application of a load on the top surface such that deflection is reduced as the load is increased for at least a range of loads until a yield load is reached.

The invention provides a fracture opening simulation device for hard brittle mudstone and shale with organic matter, it includes a simulated support, the lower part of the simulated support is connected with a storage bucket bottom block plate through a screw, the middle of the simulated support is provided with a support socket with a circular structure, the upper surface of the storage bucket bottom block plate is provided with a circular convex structure of a block plate boss, the block plate boss is closely inserted in the support socket, the upper surface of the simulated support is fixed connected with a core column storage barrel.