Mesh-less laparoscopic treatment of apical prolapse

The pelvic organ prolapse (POP) is a common gynaecological problem, affecting nearly 50% of women over 40. The sacrocolpopexy using a synthetic mesh is now considered the “gold standard” for management of women with apical prolapse. In April 2019 the FDA placed a ban on the production of transvaginal meshes for prolapse due to late complications. The meshes for abdominal repair of POP are still used, but in future they may also be prohibited. The goal of the following video is to present a mesh-less modification of two techniques used for apical organ prolapse, the sacrocolpopexy and the pectopexy.

Performance Assessment of a Planing Hull Using the Smoothed Particle Hydrodynamics Method

Computational Fluid Dynamics simulations of planing hulls are generally considered less reliable than simulations of displacement hulls. This is due to the flow complexity around planing hulls, especially in the bow region, where the sprays are formed. The recent and constant increasing of computational capabilities allows simulating planing hull features, with more accurate turbulence models and advanced meshing procedures. However, mesh-based approaches based on the finite volume methods have shown to be limited in capturing all the phenomena around a planing hull. As such, the focus of this study is on evaluating the ability of the Smoothed Particle Hydrodynamics mesh-less method to numerically solve the 3-D flow around a planing hull and simulate more accurately the spray structures, which is a rather challenging task to be performed with mesh-based tools. A novel application of the DualSPHysics code for simulating a planing hull resistance test has been proposed and applied to the parent hull of the Naples warped planing hull Systematic Series. The drag and the running attitudes (heave and dynamic trim angle) are computed for a wide range of Froude’s numbers and discussed concerning experimental values.

Improving Algorithms for Learning Radial Basic Functions Networks to Solve the Boundary Value Problems

Digital twins are widely used in modern industry. A digital twin is a computer model that copies the behavior of a physical object. Digital twins of objects with distributed parameters are mathematically boundary value problems for partial differential equation. Traditionally, such problems are solved by finite difference and finite element methods, which require a complex grid construction procedure. The numerical solution of boundary value problems employs mesh less methods that do not require grid construction. Among mesh fewer methods, projection methods that use radial basis functions (RBFs) as basic functions are popular. Methods using RBF allow us to obtain a differentiable solution at any point in the solution domain, applicable to problems of arbitrary dimension with complex computational domains. When solving the problem, the parameters of the basic functions are selected, and the weights are calculated so that the residuals obtained after the substitution of the approximate solution at the test points in the equation are zero.

Mesh-Less Analysis of Products: A Revolution Within Computer Based Design Analysis

For many years, FEA (finite element analysis) has been the dominant way of evaluating the mechanical properties of products. Engineers and design analysts are well familiar with the technology, and it is used for a lot of different types of phenomena. It is not easy to use FEA as it requires a lot of knowledge and skills for the analysis to be successful. One of the many problems is that it quickly becomes a large model with a large number of equations that have to be solved. A computer with a large internal memory, a fast CPU and fast hard disk drives is expensive to purchase and to keep up to date. Another problem is when thin-walled solids have to be analyzed. You usually need 2–3 elements in thickness to be able to obtain all stresses, which requires a lot of elements and nodes and makes the computations large or even too large. To solve these types of problem, a conversion to surfaces has to be made, where 2D shell elements may be used. Converting solids to surfaces can be demanding and time-consuming. It is a compromise, but it is solvable as a 2D model. As we all know, all body-in-white, e.g., automotive and aerospace industry, is analyzed by this method. A new type of software has recently reached the market, mesh-less design analysis, which makes it possible to perform design analysis in all kind of solids, very quickly and by using much less solving time and computer power. As this type of software doesn’t mesh the geometry, much time can be saved both on the geometry but also on waiting time for the problem to be solved. The main question is, “is it too good to be true”? In this paper, the focus is on comparing two types of design analysis software, traditional FEA, and mesh-less design analysis. Different samples of design problems have been analyzed and compared; results and conclusions are reported.

Influence of Convex and Concave Curvatures in a Coastal Dike Line on Wave Run-up

Due to climatic change and the increased usage of coastal areas, there is an increasing risk of dike failures along the coasts worldwide. Wave run-up plays a key role in the planning and design of a coastal structure. Coastal engineers use empirical equations for the determination of wave run-up. These formulae generally include the influence of various hydraulic, geometrical and structural parameters, but neglect the effect of the curvature of coastal dikes on wave run-up and overtopping. The scope of this research is to find the effects of the dike curvature on wave run-up for regular wave attack by employing numerical model studies for various dike-opening angles and comparing it with physical model test results. A numerical simulation is carried out using DualSPHysics, a mesh-less model and OpenFOAM, a mesh-based model. A new influence factor is introduced to determine the influence of curvature along a dike line. For convexly curved dikes (αd = 210° to 270°) under perpendicular wave attack, a higher wave run-up was observed for larger opening angles at the center of curvature whereas for concavely curved dikes (αd = 90° to 150°) under perpendicular wave attack, wave run-up increases at the center of curvature as the opening angle decreases. This research aims to contribute a more precise analysis and understanding the influence of the curvature in a dike line and thus ensuring a higher level of protection in the future development of coastal structures.

Interaction of Fixed Cylinder With Waves Through Weakly Coupled FNPT and Lagrangian Navier-Stokes

This paper presents a 2D/3D hybrid numerical model for studying the interaction of non-breaking waves with cylindrical structure. The work combines the strengths of mesh-based and particle-based methods, where the wave propagation is solved using 2D mesh-based potential theory model and the interaction with the structure is solved using 3D particle-based Navier-Stokes model. The paper presents the formulation of the two models and the weak-coupling methodology, along with recent improvements in the 3D MLPG_R (Mesh-less Petrov-Galerkin based on Rankine source solution) particle based method. The numerical results from interaction of fixed cylinder with solitary and focussed waves are compared with experimental data. The work demonstrates a significant reduction in simulation time for wave-structure interaction problems achieved using this hybrid approach without compromising on accuracy.