A metnod for oererm'nation of the thermal diffusivity 01 the so io pnase ot poroJs samples, baseo on frequencydependent scattering of opt.cal y i n o x e d thermal waves, :s presented. The s-riace temperature variat on of powdermetallurg'c Fe samples, dLe 10 modJ aled aser heat ng, was derecred by a photoaco-sr,c cell 'n the frequency range 30-320 hr Tne tnerma. diffJSiV ty values obtained from compar son w th a theoret'cai model [Appl. Phys. A 54 6 (1992~) are close lo those of a homogeneous sample.

No abstract

Abstract. Primary attention is given to the following methods: method by drilling cylindrical holes (drill method) and integrated ultrasonic method using volume (longitudinal and transverse), surface, and sub-surface waves. Drill method allows determination of residual mechanical stress in small depth of material surfaces, assessing type, size, and orientation of principal stresses. For the first time, parallel studies are carried out of mechanical stress in materials using the electroacoustic effect of volume, surface and sub-surface waves on the one hand, and effective mechanical stresses on the other. The experimental results present electroacoustic coefficients for different types of waves in the material of gas pipeline tube of 243 mm diameter and 14 mm thickness. These are used to evaluate mechanical stresses in pipelines, according to active GOST standards.

Abstract.A method for the assessment of the mechanical stressed state (MSS) of pipeline materials conforming to GOST R 52890-2007 is presented in the study. It is based on the measurement of the propagation time of longitudinal and two transversal waves along the pipe radius, while the procedure needs high accuracy performance. The method is validated by testing a 38KhS steel pipe and using experimentally found acoustic-elastic coefficients. The dependence of the MSS on the load acting along the pipe circumference is also presented..