Influence of Stacking Sequence on Strength and Stability of Suspension System Control arm CFRP Laminate Rods

The paper deals with buckling and strength analysis of suspension system rods made of carbon fibre reinforced polymer (CFRP) laminate. The whole suspension system of urban solar vehicle, Eagle Two, designed by Lodz University of Technology students was considered. The calculations and analysis focused on suspension rods, where the traditional metal material was replaced with CFRP laminate. The influence of layer arrangement on rod strength, static, and dynamic buckling were analysed. The research was conducted using numerical simulations employing finite element method software. The static and dynamic load was considered. The obtained results show that the plies’ order in the laminate influences both the strength and stiffness of the considered rod. The best results considering both failure force and longitudinal elasticity modulus were obtained for the stacking sequences with axially oriented (0°) plies on the outside of the rod.

Strength Characteristics of 3D-Printed PETG-Based Products Optimization

The paper considers the dependence of the strength properties of 3D-printed parts on FDM printing modes (temperature and speed), as well as the layer arrangement. PETG (polyethylene glycol terephthalate) based filament was chosen as the basis. A 3D printer was used to produce samples with strictly defined orientation of layers — longitudinal and transverse tensile force at different temperature and printing speed. The experiment has established the effect of these two factors on the tensile strength. The strength of the samples printed transversely was higher than the strength of samples printed longitudinally. This indicates a higher interlayer adhesion.

The effect of geometric parameters of PTL on oxygen transport in PEM electrolysis cell

In this study, two-phase flow of oxygen-water is studied by using numerical simulation in the Porous Transport Layer (PTL) of the Polymer Electrolyte Membrane Electrolysis Cell (PEMEC). The effect of thickness, porosity and multi-layer arrangement of PTL on the oxygen flow pattern and its removal from the PTL is investigated. The results showed the increase in the PTL thickness causes to increase the growth of the lateral paths from the inlet to the channel, which leads to increase the oxygen saturation in the PTL. It is also obtained that for PTL with different porosity, number and volume of occupied pores by oxygen in the PTL are the two main factors affecting the oxygen saturation and trade-off between them indicate the proper porosity to be used in different operating conditions. Furthermore, studies showed the use of two-layer PTL instead of single-layer can cause reduction in oxygen saturation in the proximity of reaction sites leading to a better operation of the electrolyzer.

The Layered Anatomy of the Nose: An Ultrasound-Based Investigation

Background An increasing number of soft tissue filler procedures in the nasal region has been reported. Concomitant with demand, the number of complications has risen due to the difficulty in administering filler in a region where soft tissue layering is complex. Objectives To describe the layered soft tissue arrangement of the nose as it relates to the underlying arterial vasculature and to define safer zones for nasal filler enhancement. Methods A total of 60 (28 males and 32 females) study participants were investigated with respect to their layered anatomy in the midline of the nose using ultrasound imaging. The presence and extent of the layered arrangement was examined as well as the depth of the arterial vasculature. Results In the mid-nasal dorsum, a 5-layer arrangement was observed in 100% (n= 60) of all investigated cases, whereas it was found to be absent in the nasal radix and tip. The 5-layer arrangement showed an average extent of 26.7% - 67.5% in relation to nasal length. The nasal arteries coursed superficially in 91.7% of all cases in the nasal radix, in 80% in the mid-nasal dorsum, and in 98.3% in the nasal tip. Conclusions Soft tissue filler administration in the nose carries the highest risk for irreversible vision loss compared to any other facial region. The safety of soft tissue filler rhinoplasty procedures is enhanced by knowledge of the layered anatomy of the nose, the location and depth of the major nasal vasculature, and employment of maneuvers to decrease the risk of blindness.

A comprehensive approach to the optimization of design solutions for dry anti-flood reservoir dams

The article proposes the methodology of designing dams of dry flood control reservoirs. The algorithm is developed so as to meet all the requirements given in the Eurocode 7 and, at the same time, to be efficient in terms of necessary calculation time. Furthermore, the presented numerical procedure enables the optimization of design solutions, e.g. the depth and length of the anti-filtration barrier, by means of parametric analyses. The approach assumes the use of numerical methods, in particular, finite element (FE) analysis. Three-dimensional (3D) reconstruction of the terrain topography and subsoil layer arrangement performed in step (1) sets the base for further analyses. In step (2), the filtration phenomena are assessed based on the 3D analysis of a transient groundwater flow. In step (3), the state of displacement is evaluated and the stability is verified for all the relevant phases of construction and operation of the facility, in particular, in the course of simulated flood detention. The analyses in step (3) are carried out on 2D models corresponding to the design cross-sections of the dam. This significantly reduces the computation time (compared to 3D analysis) and, at the same time, provides a safe estimate of factor of safety. The performance of the proposed algorithm is shown on the numerical examples of the computations concerning the dam of Szalejów Górny dry anti-flood reservoir located in Poland.

The Investigation of Interlaminar Failures Caused by Production Parameters in Case of Additive Manufactured Polymers

The use of three-dimensional (3D) printing technologies is an ever-growing solution. The product realized in many cases is applicable not only for visual aid, or model, but for tool, or operating element, or as an implant for medical use. For correct calculation, a proper model that is based on the theory of elasticity is necessary. The basis of this kind of model is the knowledge of the exact material properties. The PLA filament has been used to perform this study for matrix material. Our presumption is that the different layers do not fuse completely, and they do not fill up the space available. The failures between the layers and the deposited filaments and the layer arrangement could be the reason for the direction-dependent material properties of the 3D printed objects. Based on our investigation, we can conclude that the increase of the layer thickness and printing speed adversely affect the mechanical properties of the product.