Due to geometric discontinuities introduced by welding and joining processes, stresses or strain cannot be calculated reliably calculated using modern analytical and computer methods as result of stress or strain singularity at joint locations, which leads to severe mesh sensitivity. Design and fatigue evaluation of these structures remain empirical. This disclosure addresses mesh insensitivity of stress/strain calculations for welded structures through a cut-plane traction stress method through a novel post processing of conventional finite element computation results, as well as provides a unified fatigue evaluation procedure for fatigue design and structural life evaluation for both low-cycle and high cycle fatigue regime subjected to either proportional or non-proportional multiaxial fatigue loading, as well as a simple and reliable method for treating spot welds.

A control device including a solder joint life predictor includes: a temperature sensor that measures temperature of a solder joint on an electronic circuit board that drives a heater and a motor; a storage that stores a reference acceleration factor that is an acceleration factor based on a test condition of a thermal shock test and a reference condition in an environment in which the electrical appliance is used; a calculator that calculates an actual acceleration factor from a temperature variation range and a maximum reached temperature of the solder joint during one cycle from start to end of driving of the heater or the motor; and a determiner that predicts the life of the solder joint by comparing the integrated value of the acceleration factor ratios with a threshold.

There is provided a method for estimating a hardness of a cold worked component including: preparing a test piece for hardness measurement having a dent portion of a shape corresponding to a shape of the contact surface of the punch by using a mounting base on which a test piece is mounted and a punch of which a contact surface to be in contact with the test piece is a curved surface, and compressing the test piece mounted on the mounting base using the punch; measuring hardnesses of the test piece for hardness measurement at a plurality of hardness measurement positions in a measurement direction while taking, as the measurement direction, a direction in the dent portion in which a sheet thickness changes; performing numerical analysis to calculate equivalent plastic strains of the test piece for hardness measurement, and acquiring a hardness-equivalent plastic strain curve on the basis of the hardnesses and the equivalent plastic strains at the hardness measurement positions; and specifying a hardness from the calculated value of equivalent plastic strain of an arbitrary part of the cold worked component on the basis of the hardness-equivalent plastic strain curve by performing numerical analysis to calculate a value of equivalent plastic strain of a cold worked component.

In a breaking prediction method of predicting a breaking portion of a component, which is obtained by forming a metal sheet, by using a finite element method, the breaking portion is easily and reliably extracted. This breaking prediction method includes a first step of performing forming analysis by using a finite element method in each of a case where the metal sheet is divided on the basis of a first mesh coarseness and a case where the metal sheet is divided on the basis of a second mesh coarseness which is coarser than the first mesh coarseness, a second step of obtaining a maximum main stress for each mesh in each of the case of the first mesh coarseness and the case of the second mesh coarseness, and a third step of obtaining a difference value between the maximum main stress in the case of the first mesh coarseness and the maximum main stress in the case of the second mesh coarseness in each portion of the component, and extracting a portion in the case of the first mesh coarseness, which corresponds to a portion in which the difference value is larger than a predetermined value, as the breaking portion.

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.

Nano-indentation test to determine mechanical properties of reservoir rock can be implemented as multi-stage or single-stage tests. An experimental nano-indentation test (multi-stage or single-stage) is performed on a solid sample. A numerical nano-indentation test (multi-stage or single-stage) is performed on a numerical model of the solid sample. One or more experimental force-displacement curves obtained in response to performing the experimental nano-indentation test and one or more numerical force-displacement curves obtained in response to performing the numerical test are compared. Multiple mechanical properties of the solid sample are determined based on a result of the comparing.

Methods of testing a monument that is attached to a floor of the aircraft. The testing uses a compliance matrix based on attachment points where the monument is attached to the floor of the aircraft. The testing uses a test monument that is equipped with extension members and load cells positioned at the corresponding attachment points. A test load is applied to the test monument and reaction loads are determined at each attachment point. During the test period, the compliance matrix and reaction loads are used to calculate displacements at each attachment point. Each of the extension members are then adjusted by the corresponding displacement. At the end of the test period, determination is made as to whether the test monument is capable of sustaining the predetermined load and adjusted displacements at the attachment points.

There is provided a method for estimating a hardness of a cold worked component including: preparing a test piece for hardness measurement having a dent portion of a shape corresponding to a shape of the contact surface of the punch by using a mounting base on which a test piece is mounted and a punch of which a contact surface to be in contact with the test piece is a curved surface, and compressing the test piece mounted on the mounting base using the punch; measuring hardnesses of the test piece for hardness measurement at a plurality of hardness measurement positions in a measurement direction while taking, as the measurement direction, a direction in the dent portion in which a sheet thickness changes; performing numerical analysis to calculate equivalent plastic strains of the test piece for hardness measurement, and acquiring a hardness-equivalent plastic strain curve on the basis of the hardnesses and the equivalent plastic strains at the hardness measurement positions; and specifying a hardness from the calculated value of equivalent plastic strain of an arbitrary part of the cold worked component on the basis of the hardness-equivalent plastic strain curve by performing numerical analysis to calculate a value of equivalent plastic strain of a cold worked component.

A method, apparatus, system, and computer program product for estimating material properties. Training data comprising results of testing samples for a set of materials over a range of loads applied to the samples is identified by a computer system. A machine learning model is trained by the computer system to output the material properties for materials in structures using the training data.

Due to geometric discontinuities introduced by welding and joining processes, stresses or strain cannot be calculated reliably calculated using modern analytical and computer methods as result of stress or strain singularity at joint locations, which leads to severe mesh sensitivity. Design and fatigue evaluation of these structures remain empirical. This disclosure addresses mesh insensitivity of stress/strain calculations for welded structures through a cut-plane traction stress method through a novel post processing of conventional finite element computation results, as well as provides a unified fatigue evaluation procedure for fatigue design and structural life evaluation for both low-cycle and high cycle fatigue regime subjected to either proportional or non-proportional multiaxial fatigue loading, as well as a simple and reliable method for treating spot welds.