# STRESS CONCENTRATION FACTORS FOR TWO EQUAL CIRCULAR HOLES IN AN INFINITE PLATE

Theoretical stress concentration factors (Kt) of two equal circular holes in infinite plate can be calculated by this calculator for tension loads.

### Two Circular Holes in an Infinite Plate:

 INPUT PARAMETERS Parameter Value Hole diameter [d] mm cm m inch ft Distance between hole centers [L] Plate thickness [t] In-plane normal stress [σ] MPa psi ksi

Note: Use dot "." as decimal separator.

 RESULTS LOADING TYPE - IN-PLANE NORMAL STRESSES Parameter Value UNIAXIAL TENSION PARALLEL TO ROW OF HOLES (σ1=σ ,σ2=0) Stress concentration factor [Kt] * --- --- Maximum tension stress [σ] --- MPa psi ksi UNIAXIAL TENSION NORMAL TO ROW OF HOLES (σ1=0 ,σ2=σ) Stress concentration factor for point-B [KtB]* --- --- Nominal tension stress [σnom] --- MPa psi ksi Maximum tension stress at point-B [σB] --- BIAXIAL STRESS ( σ2 = σ1) Stress concentration factor for point-B [KtB]* --- --- Nominal tension stress [σnom] --- MPa psi ksi Maximum tension stress at point-B [σB] ---

Note 1: * Geometry rises σnom by a factor of Kt . (Kt = σmaxnom)

Note 2: KtB  = (σmaxnom) Theoretical stress concentration factor at point B in elastic range

### Definitions:

Stress Concentration Factor: Dimensional changes and discontinuities of a member in a loaded structure causes variations of stress and high stresses concentrate near these dimensional changes. This situation of high stresses near dimensional changes and discontinuities of a member (holes, sharp corners, cracks etc.) is called stress concentration. The ratio of peak stress near stress riser to average stress over the member is called stress concentration factor.

Kt: Theoretical stress concentration factor in elastic range = (σmaxnom)

### List of Equations:

 Tension for 0 ≤ d/L<1 $${ \sigma }_{ max }={ K }_{ t }\sigma$$ Uniaxial tension parallel to row of holes (σ1 = σ , σ2 = 0) $${ K }_{ t }=3.000-0.712d/L+0.271{ (d/L) }^{ 2 }$$ Uniaxial tension normal to row of holes (σ2 = σ , σ1 = 0) $${ \sigma }_{ max }={ \sigma }_{ B }={ K }_{ t }{ \sigma }_{ nom }\quad ,\quad { \sigma }_{ nom }\quad =\frac { \sigma \sqrt { 1-{ \left( d/L \right) }^{ 2 } } }{ 1-d/L }$$ $${ K }_{ t }=3.000-3.0018d/L+1.0099{ (d/L) }^{ 2 }$$ Biaxial tension (σ2 = σ, σ1 = σ) $${ \sigma }_{ max }={ \sigma }_{ B }={ K }_{ t }{ \sigma }_{ nom }\quad ,\quad { \sigma }_{ nom }\quad =\frac { \sigma \sqrt { 1-{ \left( d/L \right) }^{ 2 } } }{ 1-d/L }$$ $${ K }_{ t }=2.000-2.119d/L+2.493{ (d/L) }^{ 2 }-1.372{ (d/L) }^{ 3 }$$