( , , , ) (m) B B 1 2 ε λ α α σ =σ Φ , (14) where [ F( , , )] ( , , , ) 1 2 1 2 1 1 ελαα =+ + βαα Θ Φ , 1 1 2a d α = ; 2 2 2a d α = ; + ⋅ +β +β ⋅ β+β+ α+ β+β+ α ⋅π − ⋅ π ⋅ +β α − α β α α = 7 2 4 4 2 2 4 1 2 3 2 2 2 2 1 1 2 3 45 2 1 15 5 20 27 15 52 57 3 2 1 3 ) ) ( ( ) ] ( ) [( F( , , ) ⋅ +β +β +β β + β + β + β+ ⋅α− β+ β+ β+ β+ ⋅α + ) )( ) ( ( ) ] ( ) [( 3 5 1 1785 2149 1433 409 35 42 4125 7495 5597 1877 210 3 6 2 2 3 4 6 1 2 3 4 , ) o( 6 2 6 1 10 6 945 2 + α α ⋅ π ⋅ ; 1 1 2 1 2 2 1 1 1 1 1 ε < − µ −εµ − µ ελ −µ −µ β= , ) ( ) )( ( . (15) The comparison the theoretical values of tensile strength obtained by Eqn. 14 with famous [7] experimental data for cast-irons with graphite inclusions was carried out. Experimental results were obtained for different cast-iron alloys with 4% mass content of carbon and diverse forms of graphite inclusions – from circular to laminar mode (see symbols ∇, , ο at Figure 2). It is easy to convince somebody that there is a close correspondence between calculated and experimental results. 5 10 15 20 25 30 100 200 300 400 500 600 σ B , MPa λ µ =0.3 µ1 =0.2 ε =0.1 Figure 2: The comparison of theoretical tensile strength determination and experimental data for grey cast-iron with graphite inclusions We also elaborated the estimation of tensile strength values for cast-irons with various mass content of phosphorus. At increasing a content of phosphorus the phosphide eutectic inclusions are formed. Experiments for grey cast-irons with phosphide eutectic were carried out at Technical University of Zaporizhzhya (Ukraine) under the leadership of prof. Volchok I.P. We made a comparison between the theoretical results and experimental data by means of such values of parameters: 1 10 165 0 1 470 1 1 1 λ = ÷ = µ= = µ = σ = G 80 MPa, 0.25, GPa, MPa, . , G B . A close correspondence between calculated and experimental results was obtained once again. CONCLUSIONS 1. A mathematical model of elastic inclusion deformation of arbitrary relative rigidity was proposed. 2. A stressed state determination of a body with thin elastic inclusion was carried out. 3. A fracture criterion for quasibrittle materials with inhomogeneities was stated.
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