Papers by Keyword: Experimental Validation

Abstract: This study investigates the vibration characteristics of 3D-printed polylactic acid (PLA) cantilever beams using a hybrid analytical–numerical–experimental framework. Two low-cost sensing techniques—an MPU6050 accelerometer and a GoPro Hero10 vision-based system—are systematically evaluated against analytical Euler–Bernoulli and numerical ANSYS models. The analytical and numerical approaches show strong consistency for the first three natural frequencies (Mode 1: 10.22–10.31 Hz; Mode 2: 64.04–64.58 Hz; Mode 3: 179.34–180.95 Hz). Experimentally, the GoPro accurately captures the first mode (10.5 Hz), while the accelerometer successfully detects the first two modes but deviates in the third mode due to nonlinear mass-loading and sensor–structure coupling effects. The findings highlight both the capability and limitations of low-cost SHM tools and provide new insights into nonlinear behaviour in lightweight polymeric beams. The novelty of this work lies in its multi-method validation and explicit quantification of nonlinear deviations, offering a practical framework for accessible vibration-based monitoring.

Abstract: This paper introduces a novel fatigue failure criterion that leverages the evolution of residual stresses under cyclic loading to more accurately predict fatigue life in advanced materials. Traditional fatigue models often overlook the dynamic nature of residual stresses, which can significantly influence crack initiation and propagation. The proposed criterion incorporates a combination of experimentation and mathematical modeling to capture the complex interplay between cyclic loading, material microstructure, and fatigue damage. The criterion's effectiveness is validated through a series of fatigue tests on representative materials, demonstrating its superior predictive capability compared to conventional methods. This research offers a new paradigm for fatigue analysis, enabling more reliable design and performance assessment of critical components in various engineering applications.

Abstract: This paper presents an innovative approach to analyzing metal O-ring sealing performance by integrating fractal theory with fluid mechanics to model interface micro-convex characteristics. Unlike conventional methods, this approach more accurately represents the actual surface morphology of the sealing interface, enabling more precise leakage predictions. The research combines finite element analysis of the sealing surface contact states with hydrodynamic simulations of microchannel leakage behavior. Through experimental validation, the impact of sealing medium, inlet pressure, surface roughness, and compaction load on the contact area and leakage rate is systematically investigated. The key findings reveal that gases exhibit higher leakage propensity than liquids due to their superior fluidity, and the seal leakage rate increases with inlet pressure, reaching 18.86×10^-5 kg/s. Reducing surface roughness enhances interface contact and minimizes micro-leakage gaps, thereby improving sealing performance. Additionally, thresholds for compaction load are identified, beyond which further load increases result in negligible sealing gains. By bridging interface contact mechanics with microchannel leakage dynamics while accounting for realistic surface morphology, this work provides a framework for improving metal sealing ring performance prediction and optimization.

Abstract: This paper presents a study of design of a motorcycle headlight fairing for single point incremental forming by employing a simplified design guideline in conjunction with a finite element simulation of the forming process. Comparison with the experimental formed motorcycle headlight fairing is performed based on a detailed analysis of geometric accuracy of the formed parts. The study may serve as a demonstration of capabilities of single point incremental forming with respect to dimensional accuracy when forming complex parts.

Abstract: Flash butt welding (FBW) of railway rails was investigated in this work. For this purpose samples of R260 rail steel and 60E1 profile were instrumented and subsequently welded on a Schlatter GAA 100 welding machine under industrial conditions. The intention is to gain in depth process knowledge by more accurately depicting thermal cycles for an entire welding sequence in the immediate proximity of the weld as well as in the heat affected zone (HAZ). A detailed characterization of the single stages of the heat up phase of the process is important. Additionally, the secondary welding voltage was measured simultaneously during the experiments to characterize the transient heat input. Moreover, these data were used in the analysis of the temperature signals to better cope with electrical interferences. Additionally, a finite element (FE) model of this FBW process was developed in the present work. Its implementation and solution is realized with the help of ESI’s FE-software SYSWELD. A strong coupled thermo-electrokinetical and metallurgical calculation routine was used. The model comprises the transition resistance at the welding surfaces as the main heat source to the process. Temperature dependent material properties and a corresponding metallurgical model based on an experimental CCT diagram of the rail steel R350HT are implemented in the simulation as well.

Abstract: In Europe, the simultaneous introduction of new energy efficiency standards and majored seismic requirements has lead concrete constructors to find innovative solutions. In case of internal insulation, slab to wall connections have to be designed to maintain continuity of the insulation in structural connections while ensuring the transfer of shear forces from the slab to the wall. For this purpose, INGENOVA, a French civil engineering office, has developed a robust and ductile system, called SLABE®: stainless steel Z-shaped profiles are used as shear keys, creating an innovative hybrid concrete connection. An important research program has been carried out in order to characterize the SLABE® system behaviour under cyclic loads. Nearly true scale specimens including concrete slabs and walls have been tested in order to determine the stiffness and resistance under cyclic horizontal and vertical shear actions. Tests demonstrate a very stable behaviour of the system up to its theoretical yielding capacity and a large reserve of ductility due to the material of steel members. At last the effect of the SLABE on the overall seismic answer of buildings has been investigated numerically, in order to predict both the force redistribution between external and internal concrete walls, and the magnitude of horizontal forces transmitted by the shear link.

Abstract: The paper describes influence of the structure type and its parameters on the mechanical properties of cast products (not subjected to plastic forming), made out of Al-Si-X alloys. The special attention has been focused on the dendritic structure parameters: dendritic arms spacing of the first order (DAS 1) and the second order (DAS 2). The results of investigations of mechanical properties of the test castings made using three basic casting technologies: gravity sand casting (GSC), gravity die casting (GDC) and high pressure die casting (HPDC), are presented. All the castings were made out of the same AlSi9Cu3 alloy. The test castings (adherent samples and separately cast samples) were subjected to a static tensile test and their mechanical properties were determined. In the next stage, the samples fractures and zones near the fractures (metallographic specimen) were subjected to visual testing, penetrating testing PT and metallographic microscopic tests. The microstructure, including the size of the DAS 2, was determined. Evaluation of the porosity state was also undertaken. A customer casting was also manufactured and subjected to the metallographic, tomographic (CT) and strength tests. The castings solidification simulation tests were performed for all the three casting technologies (GSC, GDC and HPDC) using the Nova Flow &Solid system. The results were used for estimation of the correlation between the cooling rate of the particular casting solidifying in the above mentioned mould types and for the DAS size. The coupled influence of the structure parameters on the mechanical properties, regarding the occurrence of porosity, was also analyzed.

Abstract: Heat treatment is one of the major sources of dimensional inaccuracy in the manufacturing of fine blanked parts. Tools and equipment often need to be iteratively corrected in order to achieve the desired quality. Numerical simulation of the heat treatment process can substantially reduce these efforts. The simulation accuracy on the other hand is strongly dependent on the accurate characterization of the thermo-mechanical boundary conditions as well as material properties. The present contribution aims to propose a novel approach in the calibration of numerical models by using a modified Jominy test as well as heat treatment experiments with parts having residual stresses from a bending process. The results are validated by comparing numerical phase content and hardness values with the corresponding experiments.

Abstract: Marine current energy is clean and reliable energy source. It can be alternative energy source to produce electricity if tapped with a suitable marine current energy converter. Pacific Island countries (PIC) like Fiji can reduce the amount of Fossil fuel used. However for most energy converters designed perform well at marine current velocities above 2m/s and it needs to be installed at depths of 20 – 40m also installation and the maintenance cost of such devise will be quite high if it needs to be installed in Fiji. Therefore a ducted cross flow turbine was designed, which can give desired output at minimum installation and maintenance cost. A dusted cross flow turbine has been design taking into account for its operating condition. The turbine was modelled and analyzed in commercial; Computational Fluid dynamic (CFD) code ANSYS-CFX. The code was first validated and with experiment results and finally performance analysis of full scale turbine was carried out. The designed turbine can have maximum efficiency of 56% producing rated power of 21kW; it produces 0.77kW at cut in speed of 0.65m/s.

Abstract: This study intended to establish finite element analysis (FEA) model of warm hydro mechanical deep drawing process (WHMD) of cylindrical cups by means of commercial FEA package Ls-Dyna The validity of established FEA model is verified by means of WHMD experiments through several studies. It was noted that the established model successfully simulated the real process leading to significant cost and time spent on trial-error stage in hydromechanical deep-drawing of lightweight alloys.