4.2. Thermomechanics of a rotating saw
A planar circular rotating disk is examined next which is excited on a small part of the circumference only, see Fig. 6. The disk with radii View the MathML source and View the MathML source and thickness View the MathML source is made of steel (density View the MathML source, Young’s modulus View the MathML source, Poisson’s ratio ν=0.33, thermal conductivity View the MathML source, specific heat View the MathML source, thermal expansion coefficient View the MathML source, coefficient of convective heat transfer View the MathML source). It rotates with angular speed View the MathML source, the reference temperature is View the MathML source. There is a stationary sectorial shape of the surface of Δϕ0=10∘ once again around a three o’clock position, where both a uniform heat source term View the MathML source and two uniform tractions View the MathML source are acting. One of them represents a type of friction load in the opposite direction of the angular speed and the other one pushes in radial direction from outside on the disk. The development of the temperature distribution and that of von Mises stress over the surface of the rotating structural disk member is shown in Fig. 7 (View the MathML source and View the MathML source) and Fig. 8 (View the MathML source and View the MathML source), respectively where for the time interval shown the resulting heating is obviously concentrated in a narrow circumferential layer along the subjected surface. Due to the higher speed as in the case of the disk brake, it takes a shorter time to reach an increased temperature around the complete circumference while the radial progress of heating to be caused by heat conduction is similar to that of the brake model. In addition, it can be observed that for small times, View the MathML source, the stress field is dominated by centrifugal forces, i.e., the maximum von Mises stress appears at the inner radius r=Ri. For larger times View the MathML source, however, when sufficient heat has been fed into the saw disk, the stress field becomes dominated by thermal effects leading to high thermal stresses concentrated at the outer radius r=Ro.
4.2 การเห็น Thermomechanics ของการหมุนA planar circular rotating disk is examined next which is excited on a small part of the circumference only, see Fig. 6. The disk with radii View the MathML source and View the MathML source and thickness View the MathML source is made of steel (density View the MathML source, Young’s modulus View the MathML source, Poisson’s ratio ν=0.33, thermal conductivity View the MathML source, specific heat View the MathML source, thermal expansion coefficient View the MathML source, coefficient of convective heat transfer View the MathML source). It rotates with angular speed View the MathML source, the reference temperature is View the MathML source. There is a stationary sectorial shape of the surface of Δϕ0=10∘ once again around a three o’clock position, where both a uniform heat source term View the MathML source and two uniform tractions View the MathML source are acting. One of them represents a type of friction load in the opposite direction of the angular speed and the other one pushes in radial direction from outside on the disk. The development of the temperature distribution and that of von Mises stress over the surface of the rotating structural disk member is shown in Fig. 7 (View the MathML source and View the MathML source) and Fig. 8 (View the MathML source and View the MathML source), respectively where for the time interval shown the resulting heating is obviously concentrated in a narrow circumferential layer along the subjected surface. Due to the higher speed as in the case of the disk brake, it takes a shorter time to reach an increased temperature around the complete circumference while the radial progress of heating to be caused by heat conduction is similar to that of the brake model. In addition, it can be observed that for small times, View the MathML source, the stress field is dominated by centrifugal forces, i.e., the maximum von Mises stress appears at the inner radius r=Ri. For larger times View the MathML source, however, when sufficient heat has been fed into the saw disk, the stress field becomes dominated by thermal effects leading to high thermal stresses concentrated at the outer radius r=Ro.
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