PSI - Issue 18

S.V. Slovikov et al. / Procedia Structural Integrity 18 (2019) 198–204 S.V. Slovikov and O.A.Staroverov / Structural Integrity Procedia 00 (2019) 000–000

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The mesh is considered the object of solid mechanics. The mesh is fixed on a circular contour and bends, forming the surface of the spherical segment. Intra-abdominal pressure (IAP) is distributed evenly over the entire surface. Mechanics of behavior is described by the mechanics of membranes. The relative force arising in the mesh is determined without taking into account its thickness, and only width is taken into account. Thus, the principle of mesh loading is similar to the loading conditions of a thin-walled membrane. The object of study works under hydrostatic loading. This is the closest to the tests on loading a strip of fabric under uniaxial tension with the condition that the width of the sample is greater than the length. The smaller the ratio of the strain base to the width of the sample, the closer to the conditions of hydrostatic loading. At the same time, with an increase in the width of the sample, the effect of changing the geometry of the mesh decreases. To fulfill all the above conditions, the ratio of the base of strain to the width of the sample must be in the range from 0.1 to 0.5. In the case of a larger value of this ratio, when stretched, there is a significant narrowing of the knitted mesh, and as a result, the obtained data is distorted, which is often found in such tests (Doneva and Pashkouleva, 2018; Li et al., For the analysis of the mechanical behavior of medical meshes, a series of studies have been carried out at the Center Experimental Mechanics of the Perm National Research Polytechnic University using a special technique that takes into account specifically of the use of surgical meshes (Samartsev et al., 2017; Slovikov, 2017) This study analyzed the mechanical behavior of medical mesh samples with significantly different "displacement– load" curves. One of the types of meshes under consideration can be conditionally classified as “light” with a weight of less than 50 g/m 2 of mesh, and the other type as “heavy” (more than 90 g/m 2 ). From the category “light”, a knitted medical mesh from “Parietex” (France) labeled “TCM” made of hydrophilic monofilament polyester with a fiber diameter: 0.092 mm, weight: 38 g/m 2 , with a pore size of 1.5 cm. For the category of “heavy” mesh, one of the most common meshes of the Surgipro brand (USA) with the name “Surgipro Mesh” weighing 90 g / m2, with a fiber diameter: 0.16 mm, made of hydrophilic monofilament polypropylene, with a pore size of 0.8 cm. An image of the meshes is shown in Fig. 1. 2014; Mirjavan et al., 2017). 3. Results and discussion

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Fig. 1. The surgical meshes: (a) Surgipro Mesh «heavy»; (b) ТСМ «light»; (c) the test results: 1 - Surgipro Mesh, 2- aponeurosis, 3 – ТСМ.

During the study, tested of a series of specimens a width of 75 mm with a ratio to the base strain of 0.2 and the speed of strain 0.03 1/s. The test results of knitted meshes are shown in Fig. 1 (с). To simulate the mechanical behavior of the mesh installed on the aponeurosis, it is needing to set the loading diagram of the aponeurosis tissue. An example of an aponeurosis tissue diagram is selected from an analysis of the works of Grassel et al. (2005) and is presented in Fig. 1 (с).