tailieunhanh - Heat Analysis and Thermodynamic Effects Part 4

Tham khảo tài liệu 'heat analysis and thermodynamic effects part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Axi-Symmetrical Transient Temperature Fields and Quasi-Static Thermal Stresses Initiated by a Laser Pulse in a Homogeneous Massive Body 79 Fig. 12. Evolution of dimensionless radial stresses ar on the irradiated surface of the body c 0 for Bi and different values of dimensionless radial variable p Rozniakowski et al. 2003 . Fig. 13. Evolution of dimensionless peripheral stresses ơ gg on the irradiated surface of the body c 0 for Bi and for different values of dimensionless radial variable p Rozniakowski et al. 2003 . Evolution of dimensionless stresses with time 7 and ơ gg on the irradiated surface of the body c 0 is shown on Figs. 12 13. During irradiation process both components of stresses tensor are compressive and decrease with the distance from the centre of heated area. On the contrary inside the body in the distance equal the radius of heated area c 1 the normal stresses ơ zz are stretching see Fig. 14 . With the beginning of laser irradiation process these stresses increase quickly to the maximum value and afterward decrease with 80 Heat Analysis and Thermodynamic Effects time and reach the stationary value. The highest value of these stresses is achieved on symmetry axis p 0 . Fig. 14. Evolution of the dimensionless normal stresses zz on the plane 1 inside the irradiated body for Bi and for different values of dimensionless radial variable p Rozniakowski et al. 2003 . Fig. 15. Evolution of the dimensionless shear stresses ơ rz on the plane 1 inside the irradiated body for Bi and for different values of dimensionless radial variable p Rozniakowski et al. 2003 . On the contrary to the normal stresses .z_ the shear stresses ơ rz change their sign during laser irradiation process see Fig. 15 . In the very short time after switching laser system on the shear stresses are positive and afterward is changing to some negative value. With heating time the absolute values of stresses rr and ơ gg increase and stresses ơ zz i ơ rz Axi-Symmetrical .