A technology for evaluating forming allowance for a bending crack at a sheared end face of the press-formed component from shape information of an actual component. The method includes applying press forming including bending deformation to a metal sheet being sheared to manufacture a press-formed component, evaluating forming allowance for a bending crack at a sheared end face being an end face subjected to the shearing. A crack index value for evaluating the bending crack at the sheared end face of the press-formed component is obtained from a bend outer side strain at or near the sheared end face acquired on a basis of a component shape of the press-formed component and a press die bend radius at a portion forming the sheared end face in a press die used in the press forming, and the forming allowance for the bending crack is evaluated by the obtained crack index value.

Disclosed is an anti-buckling jig of a fracture toughness test. The anti-buckling jig includes: a first jig unit provided in a form of surrounding one side surface of a specimen; a second jig unit provided in a form of surrounding the other side surface of the specimen; and a screw provided to allow the first jig unit and the second jig unit to be coupled to each other. During the fracture toughness test of the specimen, the first jig unit and the second jig unit simultaneously support both sides of the specimen, so that the specimen is cracked in a single direction.

An example method for identifying an internal flaw in a part produced using additive manufacturing includes calculating a proof load of a part, in which the proof load is a load that when applied to the part will cause the part to fail based on presence of an internal flaw in the part, determining whether the part can withstand the proof load based on a geometry of the part and static strength data, and based on a determination that the part can withstand the proof load, applying the proof load to the part during a compliance test of the part. The proof load causes the part to fracture, when applied to the part, based on presence of the internal flaw in the part that is of a threshold size at which the internal flaw would cause cracking and potential part failure when the part is placed under the operational load.

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.

A hybrid experimental-numerical approach is disclosed to determine the Mixed Mode (I/III) dynamic fracture initiation toughness of engineering materials. Cylindrical Aluminum alloy specimens with a V-notch spiral crack on the surface at spiral angles of 0°, 11.25°, 22.5°, 33.75°, and 45° are subjected to dynamic torsion load using torsional Hopkinson bar apparatus. The torque applied to the specimen at the onset of fracture is measured through strain gages attached to the incident and transmitter bars. A stereo digital image correlation is performed to measure the full-field deformation, and the crack mouth opening displacement as a function of loading time and is used to estimate the time at which the crack initiation is started. The dynamic stress intensity factors are extracted numerically based on the dynamic interaction integral method using Abaqus. The Mode-I (K.sub.Id), Mode-III (K.sub.IIId), and Mixed Mode (K.sub.(I/III)d) dynamic initiation toughness is presented as a function of spiral angles and loading rate.

A method for identifying a necking limit strain of a metal sheet includes a step of measuring the distribution of strain in a tensile orthogonal direction in a tensile deformation process of a notch root for two or more types of sheet specimens having a notch geometry in a portion of a sheet edge; a step of obtaining a strain increment ratio of the notch root in the tensile deformation process and a strain gradient in the tensile orthogonal direction; a step of obtaining necking limit strain at which necking occurs in the notch root based on the strain increment ratio in the tensile deformation process; and a step of identifying the necking limit strain as a function of the strain gradient from the relation between the necking limit strain obtained for the two or more types of sheet specimens and the strain gradient at that time.

In an aspect, there is a method of determining allowable defects for a composite component comprising identifying at least one wrinkle characteristic of a composite component wrinkle defect; making a first plurality of specimens each having a predetermined wrinkle defect representative of the composite component wrinkle defect; measuring each of the predetermined wrinkle defects in the first plurality of specimens for at least one performance metric to generate performance data; and generating an allowable wrinkle defect profile based on the performance data from the first plurality of specimens. In other aspects, there are methods of making a specimen with a predetermined wrinkle defect.

A test coupon (1) for an ISO-standard-conforming test method for testing a material hardness of gearwheels. The test coupon (1) is designed as a two-piece test coupon (1) including a casing body (2) and a test body (3). The test coupon (1) being tested by an ISO-standard-conforming test method for determining a material hardness of the gearwheels.

Disclosed are a hole expansion ratio testing device, a hole expansion ratio testing method, and an operation program. The hole expansion ratio testing device includes a chucking unit configured to chuck a plate member having a hole, a punching unit inserted into the hole and configured to expand the hole, an image acquisition unit configured to acquire an image of the hole expanded by the punching unit, and an analysis unit configured to extract an interest area corresponding to the hole from the acquired image, linearize the interest area, and provide information on a crack as a blob changes due to the linearization.

The device for preparing sheet specimens comprises a base (1) for placing on it a sheet specimen (2) and a cutting punch (3) for cutting sheared cracks or sharp notches in said sheet specimen (2). Preferably, said cutting punch (3) comprises a beveled lower end (31) and/or a central vertical groove (32). Permits the cracks to be formed cutting directly the sheet, and not by cyclic loading, so that the preparation of the sheet specimen takes a reduced time in comparison with the conventional devices.