SU741093A1 - Method of determining the coefficient of normal contact rigidity at the butt joint of two surfaces of articles - Google Patents

Description

The invention relates to the field of measuring equipment, in particular, to methods for determining the coefficient of normal contact stiffness at the junction of two surfaces of parts. _from

A known method for determining the coefficient of normal contact stiffness, which consists in the fact that a normal compressive load is applied to the junction of the two contacting surfaces of the parts ₍₀ and the approximation value in the contact of the two surfaces of the parts and the coefficient of normal contact stiffness are determined by the corresponding formulas] T].

The closest in technical susch- -nosti ₁₅ and the result achieved to the invention is a method for determining the ratio of contact normal stiffness in the junction of the two surfaces of the parts, consisting in the fact that the surface parts 20 with a certain roughness and geometric parameters of the elastic constants of the material of the contacting parts is pressed to one another given

OF SURFACES OF PARTS by force normal to the joint plane of the parts and determine the approximation value in the contact of two parts in the mode of plastic deformation and the coefficient of normal contact stiffness ^ 2 ^.

A disadvantage of the known methods is the low accuracy of determination, due to the lack of determination of plastic hardness, which allows one to simultaneously take into account the elastic and residual parts of the full approximation at the contact of two surfaces of parts, which is especially important at an early stage of elastoplastic deformation in contact, as well as hardening of materials of parts in the contact zone.

The aim of the invention is to improve the accuracy of determination. .

This goal is achieved by measuring the plastic hardness in the contact zone, and the approximation value in contact is determined by the formula ^p

t) is the residual part of the full approximation in contact,

K ^ nKg is the elastic constant of the materials of the contacting parts.

Given the above equations, the formula for determining the approximation in the contact of two melts

P is the normal load.

Ap is the nominal contact area, the ^maximum height of the protrusions of the roughness of the contacting surfaces of the parts,

Bil) - the coefficients of the reference curve,

4l - the residual part of the full rapprochement in the contact, plastic hardness, force similarity coefficient, the drawing shows a graph of the force similarity coefficient.

Нп ЦПН singing

The method is as follows.

Two surfaces with certain geometric roughness parameters are pressed against one another by a force normal to the joint plane. The surface hardness of one part is higher than the surface hardness of the other part, so that in the 20 contact zone when loading with a given load, the surface roughness protrusions of the part with increased hardness are deformed purely elastically, and for a part with reduced hardness - elastoplastic. : The magnitude of the approach in the contact of two surfaces of the parts is determined by g de Ή - the residual part of the full approach in the contact, determined by the equation

2-GSK _pr Ch i where Pj is the conditional load transmitted by a single roughness protrusion upon contact of two surfaces of parts,

Ρηρ- reduced radius of curvature of the protrusion of the roughness, ₄₀

ΗΌ is the plastic hardness of the material of the part, which during loading is plastically deformed15 in the contact zone, cL ^ is the elastic part of the complete convergence of ₄₅ in the contact _? defined by equation

where P ₄ is the conditional load transmitted by a single protrusion of the roughness upon contact of two surfaces of the parts,

Ηη_— reduced radius of curvature of the protrusion of the roughness, the surfaces of the parts acquired ... b-.

% _F ²ⁿ th>

max ⁴ \ gder - normal load, Up - nominal contact area, ^ '1mog. ~' maximum height of the roughness protrusions of the contacting surfaces of the parts,

- coefficients of the reference curve,

- the remaining part of the full rapprochement in the contact,

- plastic hardness. 'B''o b

K> j _n is the force similarity coefficient determined by the schedule (see drawing).

The coefficient of normal contact stiffness is determined by the known dependence _

GT ’normal load, full rapprochement in contact.

Claims (1)

P is a normal load, AO is the nominal contact area, TSGG and height of extrusions of roughness of the contacting surfaces of parts, LL) are the coefficients of the reference curve, 1l is the residual part of complete contact in contact, IT5 is plastic hardness, K) n is the power similarity. The drawing shows a graph defined. And the coefficient of power similarity. The method is carried out as follows. Two surfaces with definite geometrical parameters of the scabs of a cotton are pressed one against another with a force normal to the interface plane. The surface hardness of one part than the surface on the hardness of another part, so that in the contact zone when loaded with a given load, the protrusions of the roughness of the surface of the part with increased hardness are deformed purely elastically, and in the part with reduced hardness - elastoplastic Approximation in contact between the two surfaces of the parts is determined by oC - ht-ci j rfleti - the residual part of the complete convergence in the contact, defined by equation 211; To pHB i where P is conditional, the load transmitted by a single roughness protrusion upon contact details of the surfaces of the parts, the reduced radius of curvature of the roughness of the roughness, NTE — the plastic hardness of the material of the part that deforms plastically in the contact zone in the loading process, cL is the elastic part of the complete approximation in the contact defined by the FRO equation, ((where P is conditional load transmitted by a single protrusion of roughness at the contact of two surfaces of parts, p is the reduced radius of curvature of the protrusion of roughness 11 is the residual part of the complete approximation in the contact, K. and K l are the elastic constants of the materials in contact x details. Taking into account the above equations, the formula for determining the magnitude of the approximation at the contact of two surfaces of parts takes the form J91l (R / (K,) -V IfeRn fl -. Io Р CL / hder normal load, AO - nominal contact area, Upshx maximum height of the roughness of the contacting surfaces b) il - the coefficients of the reference curve, 1n - the residual part of the complete convergence in the contact, THEIR) - plastic hardness, X) f, - the coefficient of power similar, defined by (see drawing). The coefficient of the normal contact luminosity is determined by the known dependence - 4--, J "A. Where P is the normal load, ° C is the full convergence in the contact. The method of determining the coefficient of normal contact stiffness at the junction of two surfaces of parts, namely, that the surfaces of parts with certain geometrical parameters of roughness and elastic constants of materials of the contacting parts are pressed one against another given force, normal to the interface of the parts, and determine the value the approach in contact of two parts in the mode of inflatable plastic defamation and the coefficient of normal contact stiffness, characterized in that increase in accuracy, measure plastic hardness