Brass (e.g., H80 brass) is widely used in different industrial sectors. To ensure its quality and reliability, the stress damage state of brass has to be monitored and analyzed in practice. This article introduces a new micro-magnetic method for monitoring and analyzing the tensile stress damage state of brass. Specifically, the stress-magnetic flux density model of H80 brass in the micro-magnetic environment was developed based on the stress-magnetic coupling effect. The magnetic flux density value was then used as an indicator of the different stages of tensile damage, and a new model of the spontaneous magnetic signal and structural deformation of H80 brass in the tensile process was established. The tensile test results show that the strain of H80 brass in the elastic deformation stage is 0%-5%, there is a small amount of dislocation, and the magnetic flux density does not change significantly; the strain increases to 5%-48% in the work-hardening stage, the dislocation density increases, a dislocation wall is formed at the internal lattice, and the magnetic flux density decreases with increasing tensile stress; the strain continues to increase to 48%-52% in the necking fracture stage and the internal lattice. When the strain at the necking fracture stage continues to increase to 48%-52%, the dislocation density of the internal lattice gradually stabilizes, accompanied by the appearance of sub-slip bands, and the number and density of slip bands increase; the magnetic flux density drops abruptly when fracturing occurs. These results show that the developed micro-magnetic method is accurate and reliable for monitoring and analyzing the tensile stress damage state of brass.

Being composed of blood cells and plasma, the blood flow has different rheological properties from common fluids. The viscoelastic properties of blood not only affect the flow characteristics of blood but also influence the shape of bleeding. In order to achieve the bleeding simulation with physical viscoelastic, we consider the effect of the aggregation behavior of red blood cells on the bleeding process. The elastic force caused by viscoelastic fluid elasticity is incorporated into the standard Navier–Stokes momentum equation, and an improved momentum equation that characterizes the rheological characteristics of viscoelastic blood is constructed. The effect of introducing elastic force on the particles motion is analyzed from the microscopic particle perspective by designing a two-dimensional particle system. The results of bleeding simulation show that the improved method eliminates the discontinuous boundary due to blood gushing out of the wound and forms irregular bleeding shapes in the bleeding process. In addition, the viscoelastic bleeding simulation exhibits a similar bleeding effect without distortion when the number of particles decreases, which further proves the reliability of proposed method.