A sensor for measuring the fatigue life of a structure subjected to repetitive loads is disclosed. The sensor includes a backing material arranged for securement to the structure, and a foil arranged for securement to the backing material. The foil includes a conductive path along which electrical current flows at an initial resistance measured prior to the structure being subjected to repetitive loads. A crack initiation feature in the form of a notch is located on the conductive path. In response to repetitive loads applied to the structure, one or more cracks propagate from the crack initiation feature across the conductive path to cause electrical resistance to increase whereby the progression of fatiguing of the structure may be determined.

A method for analyzing a heat exchanger includes a structural model creation step (S1) of creating a structural model of a heat exchanger; a iron-linear model creation step (S4) of creating a iron-linear model in which a non-linear spring element in an out-of-plane direction, in which a load is generated only at me time of contact between a heat transfer tube and an anti-vibration member, is applied to an opposing portion between the heat transfer tube and the anti-vibration member in a structural model, and a load distribution acquisition step (S5) of performing analysis in which a load in the out-of-plane direction is applied to the non-linear model to acquire load distribution of the heat exchanger from a value of the load in each opposing portion.

The present invention discloses a multiaxial creep-fatigue prediction method based on ABAQUS, which comprises: S1: establishing an ABAQUS finite element model, and defining the viscoplastic constitutive equation of the material to be tested by means of the user subroutine UMAT; S2: determining the model parameters required by the viscoplastic constitutive equation; S3: establishing the fatigue damage calculation model and creep damage calculation model of the multiaxial stress-strain state of the material to be tested; S4: establishing an ABAQUS finite element model under the multiaxial stress-strain state, and calculating the stress-strain tensor of each cycle based on the defined viscoplastic constitutive equation and the model parameters; S5: calculating the equivalent stress and equivalent plastic strain by means of the user subroutine USDFLD, and superimposing the fatigue damage and creep damage of each cycle according to the linear cumulative damage criterion to obtain the crack initiation life of the material to be tested based on the fatigue damage calculation model and creep damage calculation model in combination with the stress-strain tensor.

Provided is a repeated moment generation device that includes: a principal shaft; principal bearing members; lever members; principal eccentric weight rotors; auxiliary eccentric weight rotors; and drive means (such as a motor) for causing the principal eccentric weight rotors and the auxiliary eccentric weight rotors to synchronously rotate. Eccentricity directions of the principal eccentric weight rotors are different from each other by 180 degrees around shaft centers of shaft bodies thereof, eccentricity directions of the auxiliary eccentric weight rotors are different from each other by 180 degrees around shaft centers of shaft bodies thereof, and the eccentricity direction of the principal eccentric weight rotor and the eccentricity direction of the auxiliary weight rotor located on the same side as the principal eccentric weight rotor with respect to the principal shaft 1 are different from each other by 180 degrees around the shaft centers of the shaft bodies thereof.

The invention discloses a method and a system for predicting the corrosion fatigue life of prestressed concrete bridges. A corrosion level of the strand is predicted to obtain the residual tension force of a structure. A stress concentration factor is integrated to consider the stress concentration effect caused by pitting corrosion, and a growth model of the elastic stress of the strand under the coupled effect of corrosion and fatigue is proposed. A growth model of the plastic stress of the strand is established using a cross-section loss of the strand as a fatigue damage parameter based on a degenerated elastic modulus of the concrete after fatigue. Failure criteria for the concrete, the strand, and a longitudinal tension bar are defined, so that a set of methods for analyzing the life of a prestressed concrete bridge subjected to corrosive environment and fatigue load are formed.

An instrument and method for mechanical properties in situ testing of materials under a high temperature and complex mechanical loads are provided. The instrument includes: a support frame module used to provide a stable support and an effective vibration isolation for each functional module of the instrument; a high-frequency fatigue load applying module used to apply a high-frequency fatigue load on a tested sample; a static-dynamic mechanical load applying module used to apply a combination of static-dynamic tension/compression/bending loads on the tested sample; a high/low temperature applying module used to apply a variable temperature environment from a low temperature to a high temperature on the tested sample; and an in-situ monitoring module that may integrate a surface deformation damage measurement assembly, a three-dimensional strain measurement assembly, a microstructure measurement assembly, and an internal damage detection assembly according to a practical testing requirement.

A monitoring device includes an acquisition unit configured to acquire a captured image of a display panel of a control device configured to control an analyzer, an image storage unit configured to store the captured image, and a state determination unit configured to determine a state of the analyzer based on the captured image.

The present invention discloses a thermal fatigue crack generator for a large pipe. According to the present invention, the thermal fatigue crack generator for a large pipe precisely manages and controls the heating and cooling conditions for the large size test pipes having a diameter of 250 to 610 mm to significantly improve the reliability of the accuracy and a reproducibility of the thermal fatigue cycle so that a useful advantage is expected to ensure the reliability and the effectiveness of the skill verification of the non-destructive testing.

A device for fatigue test includes a sample-laying part, a sample support, and a force-applying part. The sample-laying part is disposed on the sample support; and the force-applying part is disposed on the sample-laying part; the sample-laying part includes a substrate plate and at least two arms disposed on the substrate plate; the sample support includes a bed plate and at least four roller assemblies disposed on the bed plate; each roller assembly includes a roller, a roller support, and an adjusting bolt; the roller support is disposed on the bed plate; the roller is disposed on the roller support; the adjusting bolt is disposed between the roller and the roller support; and the sample support further includes at least one barrier, and both ends of the barrier are connected to two adjacent roller supports, respectively.

Provided is a repetitive moment generating device that can be used for a fatigue testing machine and allows for a change in an amplitude of a repetitive moment to be imparted on a test piece even during rotation of an eccentric weight. A repetitive moment generating device includes: eccentric weight members provided at shaft bodies in a state where the eccentric weight members intersect the rotatably held shaft bodies and in a state where the eccentric weight members are slidable in a direction that intersects the shaft bodies; sliders that are attached to the shaft bodies in a state where the sliders are slidable in a direction of shaft centers of the shaft bodies and in a state where the shaft bodies are able to idle; link mechanisms that convert sliding motion of the sliders in the directions of the shaft centers into sliding motion in a direction that intersects the shaft bodies and transmit the sliding motion to the eccentric weight members; handle that are operation means for causing the sliders to slide in the directions of the shaft centers of the shaft bodies; and the like.