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∈.

The invention involves a method for testing a damage tolerance property in an aluminum alloy part with the following steps: measure at least one property representative of a the part's tensile strength; use the property measured in step a) as input datum (x.sub.i) of a neural network estimator; estimate, using the estimator, the representative property of the part's tensile strength; the method being characterized in that it includes: consideration of an acceptance threshold and comparison of the property estimated at step c) to the acceptance threshold, taking into account a confidence interval; based on the comparison: consider that the part passes the test; or consider that the part does not pass the test.

A method for non-destructively determining a mechanical property of a solid rocket motor propellant grain may comprise applying, via a gas, a force to a surface of the solid rocket motor propellant grain, wherein a deformation is formed on the surface of the solid rocket motor propellant grain in response to the applying, and measuring a pressure of the gas. This process may be performed over time to determine a lifespan of the propellant grain.

The disclosure provides a variable dip fault slip simulation test method, which relates to the technical field of indoor simulation test of underground engineering. The variable dip fault slip simulation test method of the disclosure adopts a sample device and a loading device, which includes the following steps: Step 1. sample preparation; Step 2. sample assembly; Step 3. loading preparation; Step 4. sample loading. The variable dip fault slip simulation test method of the disclosure can prepare rock like samples with different dip interfaces, simulate the slip failure process of faults with different dip angles, as well as the normal dip slip and reverse dip slip of faults, facilitate the operation of slip simulation test, and collect test data automatically and accurately.

A crack estimation device which accurately estimates a crack inside a structure is provided. The crack estimation device includes: a measurement unit which measures deformation of a measurement plane as a measurement plane deformation vector; a model generation unit which sets deformation of the measurement plane when a crack is generated in a crack generation plane, as a measurement plane estimated change vector for multiple types of crack candidates; and a crack state analysis unit which obtains a similarity between the measurement plane deformation vector and the measurement plane estimated change vector, normalizes the similarity, and estimates the crack generated in the crack generation plane from a result obtained by multiplying a vector of a state quantity indicating a state of the crack generation plane by the normalized similarity for each crack candidate, and adding together results of the multiplication for all the crack candidates.

An approach to the prediction of soil density and subsoil crop growth may be provided. The approach may include subsoil sensor which can monitor changes in soil pressure and moisture conditions. The sensor data can be sent to a computer module which can process the data using a machine learning model predicting the soil density around a subsoil crop and the yield of the subsoil crop. A soil maintenance plan can be generated from the soil density prediction and/or the crop yield prediction. The soil maintenance plan can be sent to soil management robots, which can execute the soil maintenance plan.

The invention relates to a device for ascertaining mechanical properties, for example, the natural frequency, the damping or the natural vibration mode of a test specimen containing ferromagnetic material components, in particular a brake pad for a motor vehicle. An electromagnetic actuator, in particular an electromagnet, is provided for exerting a magnetic attractive force onto the test specimen so that the actuator exerts a force impulse that imparts the test specimen with vibrations whose spectrum of vibration contains at least one natural frequency vibration of the test specimen.

Methods and systems are provided for characterizing interfacial tension (IFT) of reservoir fluids, which involves obtaining fluid property data that represents fluid properties of a reservoir fluid sample measured downhole at reservoir conditions, and inputting the fluid property data to a computational model that determines a value of oil-water IFT of the reservoir fluid sample based on the fluid property data. In embodiments, the fluid property data represents single-phase fluid properties of the reservoir fluid sample, such as fluid density and viscosity of an oil phase of the reservoir fluid sample and fluid density of a water phase of the reservoir fluid sample. In embodiments, the computation model can be based on machine learning or analytics combined with a thermodynamics-based physics model.

Provided is a method for evaluating a hydrogen embrittlement fracture risk of an iron reinforcing bar that is performed by a hydrogen embrittlement fracture risk evaluation apparatus, the method including: a fracture probability curved surface generation step of obtaining a fracture probability curved surface representing a probability of the iron reinforcing bar fracturing by performing regression analysis on results obtained by repeatedly carrying out a hydrogen embrittlement test while changing an amount of hydrogen absorbed in the iron reinforcing bar provided in a concrete structure and a tensile stress applied to the iron reinforcing bar and using the amount of hydrogen and the tensile stress as variables; a lower limit stress acquisition step of acquiring, from the fracture probability curved surface, a lower limit stress property representing a relationship between a lower limit stress that is a lower limit of the tensile stress at which no fracture occurs in the iron reinforcing bar at a predetermined probability and the amount of hydrogen; and an evaluation step.

The disclosure provides a variable dip fault slip simulation test method, which relates to the technical field of indoor simulation test of underground engineering. The variable dip fault slip simulation test method of the disclosure adopts a sample device and a loading device, which includes the following steps: Step 1. sample preparation; Step 2. sample assembly; Step 3. loading preparation; Step 4. sample loading. The variable dip fault slip simulation test method of the disclosure can prepare rock like samples with different dip interfaces, simulate the slip failure process of faults with different dip angles, as well as the normal dip slip and reverse dip slip of faults, facilitate the operation of slip simulation test, and collect test data automatically and accurately.