What Is an Adductor Strain?

Internal strain refers to the deformation caused by the internal stress of the material. The finished part is easily deformed and cracked until it breaks, so that the internal stresses that cause internal strain are managed.

In the field of plastic working, in order to study the law of metal flow, it is often necessary to study the stress-strain distribution in the deformed body during different plastic working processes. Among various physical simulation methods, the in-plane moire method has certain advantages. It can study a variety of simulation materials or physical materials with different properties, and obtain straight and clear isobaric lines. It can also measure the normal strain and shear strain inside the deformed body at the same time, so it is widely used in the field of metal forming. The principle of the in-plane moire method is to attach the grid to the surface of the measured object, and after a certain deformation, it becomes a deformed grid. This is superimposed on the undeformed reference grid to form a moire pattern. The in-plane moiré method's data processing process is to take moiré images into a computer and perform various image processing, including tracking and refining the center line, determining moiré levels, differential calculations, and so on. Finally, the displacement and strain fields inside the deformed body can be obtained. It is very difficult to completely automate the data processing of the moire method, and in essence, the moire method still has some shortcomings, such as small amount of information, uneven data distribution, and reduced accuracy due to manual intervention. Wait. In contrast, the phase method has powerful advantages.

Phase method is mainly used for shape detection of 3D curved shapes. It directly uses the modulated raster line information on the surface of the test piece, and uses mathematical methods (including fast Fourier transform, spectrum analysis, and various digital image processing) to demodulate to obtain highly distributed information. Compared with the moiré method, the phase method uses mathematical methods to resolve phases without manual intervention, so it has the characteristics of high degree of automation, large amount of data, high accuracy, and uniform data distribution. There are many researches on phase method in three-dimensional curved surface detection, but few researches on in-plane strain measurement. Enrich and develop the phase method to make it suitable for the measurement of in-plane deformation, which has considerable practical value ^[2]

With the development of modern high technology and science, microelectronics, large-scale integrated circuits, computer engineering, and various composite materials have been widely used. The destruction or damage of materials or structures is a problem worthy of attention. Macro fracture mechanics is the analysis of the deformation field and stress field singularity of crack body and crack tip. However, in the small area of the crack tip, the macroscopic fracture mechanical solution is not applicable. The failure of both brittle and ductile materials begins locally on the meso scale. Under external force, temperature, or other environmental influences, first of all, the material is meso-damaged, and local defects occur (the defects may be micro-voids or micro-cracks), which gradually develop and cause damage. Therefore, meso-mechanics is a combination of materials science and mechanics. Disciplines have aroused great interest from scholars. It is a study of how materials change from a continuum to a discontinuity under the influence of the external environment, the development process, critical conditions, and constitutive relations. Both theoretical research and experimental research are very important. Due to the study of the behavior in the microscopic area, it is generally a large deformation state, which requires high measurement accuracy, which brings great difficulties to the test. It is very important to experimentally explore the deformation field measurement in the micro area. Modern image analysis technology for the area measurement is a noteworthy research area ^[3]

1. ZnO on a Si (100) substrate prepared using a magnetically filtered cathode pulse vacuum arc deposition system (PF-CVAD) at a substrate temperature of 400 ° C, an oxygen partial pressure of 4.0 × 10-2Pa, and a target negative pressure of 400 V. The strain in the film is mainly compressive stress, and the occurrence of compressive stress is attributed to the "atom peening" mechanism in the film preparation process.

2. Part of the atoms bound to the non-equilibrium position in the ZnO film during the deposition process migrate to the equilibrium position after annealing, which leads to the reduction of the compressive stress of the film.

3. Increasing the annealing temperature can promote the grain growth of ZnO thin film and reduce the compressive stress of the thin film. When the annealing temperature rises to about 530 ° C, the internal strain of the film changes from compressive stress to tensile stress ^[2] .