Plane Punch Research Articles

Formulation Development of Tolperisone Hydrochloride Film Coated Tablet

Among all the different routes of administration, oral route of administration continues to be the most preferred route due to various advantages including ease of ingestion, avoidance of pain, versatility and most importantly patient compliance. Likewise, among all dosage forms tablet is the most popular dosage form existing today because of its convenience of self-administration, compactness and easy manufacturing. Sometimes immediate onset of action is considered obligatory immediate release tablets are the final option. Recently immediate release tablets have started gaining popularity and acceptance as a drug delivery system, mainly because they are easy to administer and lead to better patient compliance. In the present work, we engage in discussion about formulation, development, and evaluation of immediate release tablets. An immediate release dosage form allows a manufacturer to extend market exclusivity. They are also a tool for expanding markets, extending product life cycles and generating opportunities. pharmaceutical products designed for oral delivery and currently available on the prescription and over-the-counter markets are mostly the immediate release type, which are designed for immediate release of drug for rapid absorption. Tolperisone Hydrochloride Film Coated Tablets 50 mg was prepared using various excipients listed as in formula. The tablets were prepared by wet granulation method using concave plane punch on multi-station compression machine. The formulations were evaluated for their physical characteristics like thickness, hardness and friability, weight variation, content uniformity study was carried out. Evaluated for chemical analysis like Assay, disintegration and dissolution. In-vitro comparative dissolution study was performed with the help of U.S.P dissolution test apparatus-II with 900 ml of 0.1 N HCL, Acetate buffer pH 4.5 & 0.1 M HCL Acid at the 75 rpm for 45min.

Warm and cold blanking of manganese-boron steel 22MnB5 with different tool geometries

Abstract Two main processes for shaping press hardened ultra-high strength steels (UHSS) are laser cutting and cold blanking, which are either cost-intensive and time-consuming or require high blanking force. Therefore, the integration of warm blanking and hot forming in one process represents a possible alternative for shaping UHSS. Due to the integration of various process steps such as forming, blanking and quenching, a reduction of process steps is possible. This leads to a decrease of time and operating costs. Tool load can be reduced as well because of the lower tensile strength of heated steel. However, there are several disadvantages to integrating these process steps. High process temperatures encourage warpage of tool and sheet and therefore an increase in tool and maintenance costs. To investigate the influence of process integration on the blanking and retraction forces and the quality of the cutting surface, several surveys were conducted by one-hole-blanking. One possibility to deal with the disadvantages could be the use of different punch geometries (plane, conical, truncated conical) in combination with different clearances during warm blanking of typical quenched 22MnB5. Characteristic cutting and retraction forces and temperatures as well as parameters of cutting surfaces were measured and analyzed. A variation of the punch geometry and clearance does not give a significant improvement in the forces and quality of the cutting surface. However, for a high part quality with less burr, a plane punch is recommended and a conical or a truncated conical punch may reduce friction induced wear in industrial applications by producing less burnish.

Plastic deformation of a wedge by a sliding punch

We present a self-similar solution of the problem of deformation of an ideally plastic wedge by a sliding punch with regard to contact friction; such a solution generalizes the well-known solutions of the problem of wedge penetration into a plastic half-space and of compression of an ideally plastic wedge by a plane punch. The problem is of interest for modeling the processes of plastic deformation of rough surfaces of metal pieces by a rigid tool.

Contact problems for a circular plate with sliding fixation at the end face

Two mixed elasticity problems of punch indentation into a circular plate placed without clearance in a rigid cylindrical holder with smooth walls are considered. In the first problem, the plate lies without friction on a rigid base, and in the second problem, the plate is rigidly fixed to the base. The problems are solved by a method that was developed for bodies of finite dimensions and is based on the properties of closed systems of orthogonal functions. Each of the problems is reduced to two integral equations, namely, a Volterra integral equation of the first kind for the contact pressure function and a Fredholm integral equation of the first kind for the derivatives of the displacement of the plate upper surface outside the punch. The displacement function is sought as the sum of a trigonometric series and a power function with a root singularity. After truncation, the obtained illposed system of linear algebraic equation has a stable solution. A method for solving Volterra integral equations is given. The contact pressure distribution function and the dimensionless indentation force are determined. Examples of calculation of the plate interaction with the plane punch are given. Contact problems were earlier studied for a rectangle and a circular plate with a stress-free end both without taking account of their fixation [1, 2] and with regard for their fixation [3, 4]. The solution method described here was used to study the interaction of elastic hollow cylinder of finite length with a rigid bandage and a rigid insert [5, 6]. Other papers dealing with contact problems for bodies of finite dimensions, in particular, for a circular plate, should also be mentioned. In these papers, the problems under study were solved by the method of homogeneous solutions [7, 8] and by the method of coupled series-equations [9].

Uniform motion of a plane punch on the boundary of an elastic half-plane

The dynamic contact problem of a plane punch motion on the boundary of an elastic half-plane is considered. The punch velocity is constant and does not exceed the Rayleigh wave velocity. The moving punch deforms the elastic half-plane penetrating into it so that the punch base remains parallel to itself at all times. The contact problem is reduced to solving a two-dimensional integral equation for the contact stresses whose two-dimensional kernel depends on the difference of arguments in each variable. A special approximation to the kernel is used to obtain effective solutions of the integral equation. All basic characteristics of the problem including the force of the punch elastic action on the elastic half-plane and the moment stabilizing the punch in the horizontal position in the process of penetration are obtained. A similar problem was considered in [1] and earlier in the “mode of steady-state motions” in [2, 3] and in other publications.

Interaction of a rigid punch and a circular plate with a fixed side and a stress-free face

The axisymmetric contact problem of a rigid punch indentation into an elastic circular plate with a fixed side and a stress-free face is considered. The problem is solved by a method developed for finite bodies which is based on the properties of a biorthogonal system of vector functions. The problem is reduced to a Volterra integral equation (IE) of the first kind for the contract pressure function and to a system of two Volterra IE of the first kind for functions describing the derivative of the displacement of the plate upper surface outside the punch and the normal (or tangential) stress on the plate lower fixed surface. The last two functions are sought as the sum of a trigonometric series and a power-law function with a root singularity. The obtained ill-conditioned systems of linear algebraic equations are regularized by introducing small parameters and have a stable solution. A method for solving the Volterra IE is given. The contact pressure functions, the normal and tangential stresses on the plate fixed surface, and the dimensionless indentation force are found. Several examples of a plane punch computation are given.

Flat-ended circular cylindrical punch for initially stressed Neo-Hookean solids

The present paper reports the indentation of integral transform technique for a semi-infinite initially stressed elastic medium under the action of an axi-symmetric flat-ended circular cylindrical punch pressing the medium normally. The incremental deformation theory is used to solve the problems for Neo-Hookean solid. The distribution of incremental stress and strain is obtained by using the Hankel’s transformation. The effects of the punch have been studied numerically and presented in various forms of curves. The plane punch indentation has its broad applications in the field of Engineering Mechanics. There are so many firing and launching pads, which use the Neo-Hookean solid as buffer and bear the punch during the action of machines. Thus the present problem has a lot of applications to find the effect of punch on machines.

The contact problem for a circular plate with a stress-free end face

An axisymmetric contact problem for a circular elastic plate with a stress-free end face into which two symmetrically arranged punches are imbedded, is considered. The problem is solved using a method developed earlier for bodies of finite sizes, which is based on the generalized orthogonality of homogeneous solutions. The problem reduces to a Fredholm integral equation of the first kind in a function describing the displacement of the surface of the plate outside the punch. These functions are sought in the form of a sum of a Schlömilch series and a power function with a root singularity. The ill-posed infinite system of algebraic equations obtained as a result is regularized by the introduction of a small positive parameter. Since the matrix elements of the system, as well as the contact stresses, are defined by poorly converging numerical and functional series, the technique of summation of the residues of these series is used. The distribution of the contact pressure and the dimensionless imbedding force are found. Examples of the calculation of a plane punch are given.

Interaction of a rigid punch with a base-secured elastic rectangle with stress-free sides

The plane contact problem of the indentation of a rigid punch into a base-sucured elastic rectangle with stress-free sides is considered. The problem is solved by a method tested earlier and reduces to a system of two integral equations in functions describing the displacement of the surface of the rectangle outside the punch and the normal or shear stress on its base. These functions are sought in the form of the sum of trigonometric series and an exponential function with a root singularity. The ill-posed infinite systems of algebraic equations obtained as a result of this are regularized by introducing small positive parameters. Because the matrix elements of the systems, and also the contact stresses, are defined by poorly converging numerical and functional series, the previously developed method of summation of these series is used. The contact pressure distribution and the dimensionless indenting force are found. Examples of a plane punch calculation are given.

Chondrocyte function after osteochondral transfer: comparison of concave and plane punches

An incongruity between instrument and articular surfaces in osteochondral transfer (OCT) results in unevenly distributed impact forces exerted on the cartilage which may cause a loss of functional chondrocytes. We tested whether a plane instead of a concave design of the punch of an osteotome can reduce these cartilage damages. Osteochondral cylinders were transferred from a donor to a recipient site within porcine humeral heads. Histological sections of the cartilage were assessed for metabolic active chondrocytes by in situ hybridization detecting coll alpha(1)(II) mRNA subsequent to OCT and 24 h thereafter. The percentage of cartilage harbouring functional chondrocytes in the transferred grafts was 85 +/- 10 and 91 +/- 4% subsequently to OCT using punches with concave or plane surfaces, respectively, and 83 +/- 10% (concave) and 82 +/- 10% (plane) after 24 h. In the superficial layer of the cartilage the percentages were 72 +/- 13% (concave) and 84 +/- 8% (plane) subsequently to OCT, and 68 +/- 15% (concave) and 70 +/- 3% (plane) after 24 h. The analysis did not reveal any statistically significant differences. The OCT leads to considerable loss of functional chondrocytes which could not be prevented by the use of a plane instead of a concave punch. Since functional chondrocytes might be of crucial importance for the survival and integration of the graft into the recipient site further work is needed to optimize the OCT procedure.

Modal analysis of piezoelectric bodies with voids. I. Mathematical approaches

The paper is concerned with the eigenvalue problems for piezoelectric bodies with voids in contact with massive rigid plane punches and coved by the system of open-circuited and short-circuited electrodes. The linear theory of piezoelectric materials with voids for porosity change properties according to Cowin–Nunziato model is used. The generalized statements for eigenvalue problem are obtained in the extended and reduced forms. A variational principle is constructed which has the properties of minimality, similar to the well-known variational principle for problems with pure elastic media. The discreteness of the spectrum and completeness of the eigenfunctions are proved. The orthogonality relations for eigenvectors are obtained in different forms. As a consequence of variational principles, the properties of an increase or a decrease in the natural frequencies, when the mechanical, electric and “porous” boundary conditions and the moduli of piezoelectric solid with voids change, are established.

Some theorems about spectrum and finite element approach for eigenvalue problems for elastic bodies with voids

The paper concerns eigenvalue problems for elastic bodies with voids in contact with massive rigid plane punches. The linear theory of elastic materials with voids according to the Cowin–Nunziato model is used. A variational principle is constructed which has the properties of minimality, similar to the well-known variational principle for problems with pure elastic media. The discreteness of the spectrum and completeness of the eigenfunctions are proved. As a consequence of variational principles, the properties of an increase or a decrease in the natural frequencies, when the mechanical and “porous” boundary conditions and the modulus of elastic solid with voids change, are established. A finite element method is proposed for numerical solution of eigenvalue problems for elastic media with voids. Some effective block algorithms for finite element eigenvalue problems with partial coupling are described. Numerical experiments are presented for determining the first eigenfrequencies of an axisymmetric elastic body with voids.

The contact problem for a rectangle with stress-free side faces

The plane contact problem for an elastic rectangle into which two symmetrically positioned punches are impressed is considered. Homogeneous solutions are constructed that leave the side faces of the rectangle stress-free. When the modified boundary conditions using generalized orthogonality of the homogeneous solutions are satisfied, the problem reduces to a Friedholm integral equation of the first kind in the function describing the displacement of the surface of the rectangle outside the contact area. This function is sought in the form of the sum of a trigonometric series and a power function with a root singularity. The ill-posed infinite system of algebraic equations thereby obtained is regularized by introducing a small positive parameter (Ref. Kalitkin NN. Numerical Methods. Moscow: Nauka; 1978), and, after reduction, has a stable regularized solution. Since the matrix elements of the system are determined by a poorly converging number series, an effective method was developed for calculating the residues of the series. Formulae are found for the contact pressure distribution function and dimensionless indentation force. Since the first formula contains a third-order derivative of the functional series, when it is used, a numerical differentiation procedure is employed (Refs. Kalitkin NN. Numerical Methods. Moscow: Nauka; 1978; Danilina NI, Dubrovskaya NS, Kvasha OP et al. Numerical Methods. Textbook for Special Colleges. Moscow: Vysshaya Shkola; 1976). Examples of a calculation for a plane punch are given.

The impact of a plane punch on an elastic half-plane

The transient dynamic contact problem of the impact of a plane absolutely rigid punch on an elastic half-plane is considered. The solution of the integral equation of this problem in terms of the unknown Laplace transform of the contact stresses at the punch base is constructed by a special method of successive approximations. The solution of the transient dynamic contact problem is obtained after applying an inverse Laplace transformation to the solution of the integral equation over the whole time range of the impact process, and the law of the penetration of the punch into the elastic medium is determined from a Volterra-type integrodifferential equation. The conditions for the punch to begin to separate from the elastic half-plane are formulated from the solution obtained, and all the stages of the separation process are investigated in detail. The law of the punch motion on the elastic half-plane and the width of the contact area, which varies during the separation, are then determined from the solution of the Volterra-type integrodifferential equation when an additional condition is satisfied.

Doubly periodic contact problems for an elastic layer

The problem of the indentation of a doubly periodic system of punches into an elastic layer is considered. For a relatively thick layer and relatively large values of the semiperiods, an asymptotic solution is obtained. As an example, the cases of a doubly periodic system of plane, inclined and elliptical (in plan) punches and a doubly periodic system of parabolic punches are studied.

An asymptotic method of solving transient dynamic contact problems of the theory of elasticity for a strip

An asymptotic method is proposed for solving transient dynamic contact problems of the theory of elasticity for a thin strip. The solution of problems by means of the integral Laplace transformation (with respect to time) and the Fourier transformation (with respect to the longitudinal coordinate) reduces to an integral equation in the form of a convolution of the first kind in the unknown Laplace transform of contact stresses under the punch. The zeroth term of the asymptotic form of the solution of the integral equation for large values of the Laplace parameter is constructed in the form of the superposition of solutions of the corresponding Wiener-Hopf integral equations minus the solution of the corresponding integral equation on the entire axis. In solving the Wiener-Hopf integral equations, the symbols of the kernel of the integral equation in the complex plane is presented in special form — in the form of uniform expansion in terms of exponential functions. The latter enables integral equations of the second kind to be obtained for determining the Laplace-Fourier transform of the required contact stresses, which, in turn, is effectively solved by the method of successive approximations. After Laplace inversion of the zeroth term of the asymptotic form of the solution of the integral equations, the asymptotic solution of the transient dynamic contact problem is determined. By way of example, the asymptotic solution of the problem of the penetration of a plane punch into an elastic strip lying without friction on a rigid base is given. Formulae are derived for the active elastic resistance force on the punch of a medium preventing the penetration of the punch, and the law of penetration of the punch into the elastic strip is obtained, taking into account the elastic stress wave reflected from the strip face opposite the punch and passing underneath it.

Two plane punches on a nonlocal elastic half plane

The solution of a contact problem for two plane punches is summarized. After the recapitulation of the fundamental equations of nonlocal theory of elasticity, the nonlocal stress distribution under the frictionless punches is calculated. The classical and nonlocal solutions are compared with each other. The superiority of the nonlocal theory has been demonstrated.

Some properties of the natural frequencies of electroelastic bodies of bounded dimensions

Homogeneous problems of the natural oscillations of bounded electroelastic solids, in contact with rigid plane punches and coated with a system of open- and short-circuited electrodes, are considered. A variational principle is constructed which has the properties of minimality, similar to the well-known variational principle [t] for problems with only short-circuited electrodes. The discreteness of the spectrum and the completeness of the eigenfunctions are proved. As a consequence of variational principles, the properties of an increase or a decrease in the natural frequencies when the mechanical and electrical boundary conditions and the moduli of the electroelastic solid change are established. It is noted that changes in the mechanical and electrical parameters cause opposite changes in the natural frequencies. A confirmation of the fact that, for an electroelastic solid with a multi-electrode coating, the natural frequencies for short-circuited electrodes (the electric resonance frequencies) do not exceed the corresponding frequencies for open-circuited electrodes (the antiresonance frequencies) is obtained as a special case of one of the theorems proved.

A contact problem with friction and adhesion for an elastic layer with stiffeners

The contact of an elastic layer with an infinite stiffener to which a uniform constant normal load and a concentrated tangential force are applied, is considered. In the neighbourhood of the point of application of this force, on the line of the contact of the stiffener with the layer a segment is separated out, on which the effect of the Coulomb friction is taken into account. Outside this segment the stiffener and the layer are under conditions of complete adhesion. The problem is reduced to a Prandtl-type integro-differential equation specified on two semi-infinite segments, for whose solution an analytical method is proposed. The method is based on reducing the equation to a vectorial Riemann problem and then to an algebraic Poincaré-Koch system. The latter admits of an explicit solution and also inversion through recurrent relations that are effective when using numerical computations. The length of the Coulomb friction zone and the contact tangential stresses in the adhesion zone are determined. Unlike Melan's problem [1] the contact stresses have no logarithmic singularity and are continuous everywhere in the contact area. The solution of the problem of the contact of a layer with a finite stiffener subject to a uniform pressure along the whole length and to an extension by forces concentrated at the tips is also obtained. The contact area is divided into an intermediate zone of adhesion and two zones of coulomb friction. The problem is reduced to a Prandtl-type integro-differential equation specified on the segment, and it is solved by analogy with the solution of the equation of the first problem. Such a formulation of the problem implies that the contact tangential stresses are bounded at the tips of the stiffener and are continuous at the points of the boundary between the zones of adhesion and Coulomb friction. When adhesion occurs along the entire line of contact the tangential stresses, in general, have a root singularity [2]. In the problem of the contact of a plane punch with a half-plane under conditions of friction and adhesion, the contact stresses at the tips of the punch have [3] a power singularity (that differs from a root one).

Plane punch indentation of a ductile honeycomb

The stresses and deformations in an anisotropic half-space indented by a flat punch are calculated for material parameters that characterize a transversely crushed ductile honeycomb. After a small range of elastic deformations, the honeycomb crushes in localized bands that extend in characteristic directions within the half-space. Large geometric changes in the crushed cells modify their mechanical properties and constrain the deformation of adjacent cells. A lower estimate of the indentation force is obtained by comparing the peak stress beneath the indenter with the yield strength of the honeycomb. An upper estimate of the indentation force is calculated by equating the work-rate of indentation with the dissipation-rate of a flow-field that is compatible with the crushing bands.