A strain inspection device of a printed circuit board (PCB) which is easily cracked or damaged by external pressure (force) applied to the PCB while the PCB is being assembled, and an attaching method thereof. The strain inspection device of a printed circuit board (PCB) includes a fixing member; and a damage indicator fixed to the PCB by the fixing member, having a crack guide through hole, and cracked or damaged along a corner of the crack guide through hole due to deformation of the PCB.

Systems and methods for determining mechanical properties of formation rock using, for example, millimeter-scale test samples of the formation rock are disclosed. The test samples may be single edge notched beam (SENB) test samples. The systems and methods may include performing laboratory testing on the SENB test samples and recording laboratory testing data obtained from the laboratory testing and performing a simulation on a numerical model of the SENB test samples and recording the simulation data obtained from the simulation. The laboratory testing data and the simulation data may be compared, and a determination may be made as to whether a selected degree of correlation is present between the laboratory testing data and the simulation exists. Mechanical properties of the formation rock are obtained from the simulation data when the selected degree of correlation exists between the laboratory testing data and the simulation data.

Disclosed are an anisotropic mechanical expansion (anisotropic Poisson's ratio) substrate and a crack-based pressure sensor using the same. The substrate having an anisotropic Poisson's ratio includes a first layer having linear concave and convex patterns arranged in parallel to each other on a surface thereof; and a second layer having linear convex and concave patterns respectively engaged with the linear concave and convex patterns of the first layer on a surface thereof, wherein the first layer and the second layer are stacked with each other so that the linear convex and concave patterns of the second layer are respectively engaged with the linear concave and convex patterns of the first layer, wherein an elastic modulus of the first layer is different from an elastic modulus of the second layer.

A method for probabilistic fatigue life prediction using nondestructive testing data considering uncertainties from nondestructive examination (NDE) data and fatigue model parameters. The method utilizes uncertainty quantification models for detection, sizing, fatigue model parameters and inputs. A probability of detection model is developed based on a log-linear model coupling an actual flaw size with a nondestructive examination (NDE) reported size. A distribution of the actual flaw size is derived for both NDE data without flaw indications and NDE data with flaw indications by using probabilistic modeling and Bayes theorem. A turbine rotor example with real world NDE inspection data is presented to demonstrate the overall methodology.

The invention relates to a device for carrying out bending tests on panel-shaped or beam-shaped samples (1), in which two rotary drives are arranged at a distance from one another and a flange (3) is fastened to each of the drive shafts of the rotary drives, said drive shafts being oriented parallel to one another. At least two bar-shaped bending elements (2) oriented parallel to the axis of rotation of the drive shafts and arranged at a distance from the axis of rotation and at a distance from one another are provided on each of the flanges (3). A panel-shaped or beam-shaped sample (1) can be introduced between the two bar-shaped bending elements (2) on the two flanges (3). In the event of rotation of the rotary drives in opposite directions of rotation, bending forces are exerted on the sample (1) and each of the two rotary drives can be controlled individually and connected to an electronic open-loop or closed-loop control unit.

A method to utilize the results from a series of FEM models to develop a master derivative of compliance curve. The use of the unique master curve resolves the test data variability issue caused by fitting the compliance curve individually. The analytically derived derivative of compliance curve eliminates the needs to take the derivative of compliance and therefore the derivative computation error no longer exists. By applying the existing solution and the solution as disclosed and claimed herein to the same set of the raw test data, it is found that data scatter is significantly reduced.

A numerical simulation tool for progressive failure in laminates utilizes a low fidelity approach. The numerical model includes an enriched element that is initially in a low fidelity form. The enriched elements may increase fidelity by splitting locally to simulate an ongoing damage process such as delamination.

The disclosed method includes, from a topographic map showing, for a set of points {x} located in a midplane of the fracture surface, a height of the fracture surface h relative to the midplane: a step of determining, for each point x on the topographic map, a quantity ω.sub.∈ representative of an average difference in height).sub.IδxI≦∈ between the height h of the fracture surface at point x in question and the height h of the fracture surface at one or more points {x+δx} located inside a circle of radius ∈ centered on point x in question, a step of determining, according to a test distance δr, a spatial correlation function C∈ representing a spatial correlation between points {x} and points {x+δx} such as IδxI=δr, and a step of determining a correlation length ξ from the spatial correlation function C∈.

Coal rock three-dimensional strain field visual system and method are provided under a complex geological structure. The system includes a stress condition simulation system and a strain monitoring system. The stress condition simulation system includes a similar simulation experiment rack, a loading system and a circular slideway. The method includes preparing a 3D printing wire, printing a strain visual similar model, simulating a stratum dip angle and a gas-containing condition, applying stress fields, recording a cracking and dyeing condition of microcapsules inside the model, and the like. The system can realize tracing the generation and development of internal cracks in simulation models with complex geological conditions, and tracing the three-dimensional movement of internal ink dots to draw four-dimensional images of displacement fields.

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.