scholarly journals Experimental and Numerical Assessment of Supporting Road Signs Masts Family for Compliance with the Standard EN 12767

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5999
Author(s):  
Michał Stopel ◽  
Artur Cichański ◽  
Nathalie Yague ◽  
Grzegorz Kończalski
Keyword(s):  
Numerical Models ◽  
Product Family ◽  
Experimental Tests ◽  
Severity Index ◽  
Point Of View ◽  
Passive Safety ◽  
Road Signs ◽  
Numerical Assessment ◽  
The Impact ◽  
Crash Tests

The analysis aimed to assess the passive safety of supporting masts for road signs in accordance with EN 12767. Experimental tests were carried out based on the requirements of the standard for the smallest and the largest constructions within the product family. Numerical models of crash tests were prepared for whole product family using the Finite Element Method in the LS-Dyna environment. Based on the comparison of the experimental tests and the numerical calculations, the usefulness of the numerical model for estimating the actual value of the Acceleration Severity Index (ASI) and the Theoretical Head Impact Velocity (THIV) was assessed. With the use of these relationships the values of ASI and THIV for masts not tested experimentally were estimated. It was confirmed that the analyzed masts met the requirements for the passive safety of structures set out in the standard EN 12767. It was possible since as a result of the impact, the mast column detached from the base, allowing the vehicle to continue moving. The behavior of the masts was primarily influenced by the destruction of the safety connectors. The paper presents the most important elements from the point of view of designing such solutions.

scholarly journals Determination of ASI and THIV parameters based on the results of experimental and numerical research in relation to EU standards

2021 ◽  
Vol 338 ◽  
pp. 01025
Author(s):  
Michał Stopel
Keyword(s):  
Experimental Tests ◽  
Severity Index ◽  
Point Of View ◽  
The Finite Element Method ◽  
Safety Level ◽  
The Road ◽  
Road Sign ◽  
Numerical Research ◽  
Python Programming

Determining the values of ASI (Acceleration Severity Index) and THIV (Theoretical Head Impact Velocity) parameters during tests allows you to assign an appropriate class for a given type of object to determine the safety level and to give the CE marking. The paper presents the methodology for determining these parameters based on the EN 1317-1 and EN 12767 standards. The paper also presents a tool created with the use of the Python programming language, which, based on the results of experimental tests or the results of numerical calculations, allows to determine the ASI and THIV values. The values of key parameters from the point of view of normative tests were calculated based on the results of experimental tests of the road sign supporting mast and numerical analysis carried out for the same case using the Finite Element Method and LS-Dyna software, following the EN 12767 standard.

Experimental Study of the Bond of FRP Applied to Natural Stones and Masonry Prisms

2014 ◽  
Vol 624 ◽  
pp. 453-460 ◽  
Author(s):  
Matteo Panizza ◽  
Enrico Garbin ◽  
Maria Rosa Valluzzi ◽  
Claudio Modena
Keyword(s):  
Experimental Tests ◽  
Point Of View ◽  
Shear Tests ◽  
Bond Behaviour ◽  
Lime Mortar ◽  
Glass Composites ◽  
Externally Bonded ◽  
Heritage Buildings ◽  
Natural Stones ◽  
The Impact

Compared to more traditional techniques, the application of Externally Bonded-Fibre Reinforced Polymers (EB-FRP) represents a viable alternative for the strengthening of masonry structures, also in case of Cultural Heritage buildings where strict requirements need to be met, aimed at minimizing the impact of the intervention. Since the FRP-to-masonry bond behaviour strongly affects design and effectiveness of such interventions, several investigations have been carried out in recent years to study this phenomenon, generally based on the longer experience developed for concrete substrates. Mortar joints, which are geometrical and mechanical discontinuities, distinguish and characterize masonry substrates from concrete ones, and therefore deserve a special attention as far as their role in the bond behaviour is not clarified yet. This paper, aimed at giving a contribution also from a methodological point of view, presents the main experimental results of shear tests carried out on glass composites (GFRP) applied to natural calcareous stones (pietra leccese), to lime mortar blocks and to masonry prisms made by coupling stones and lime mortar. Overall 22 shear tests were performed, keeping a bonded length of 200 mm for stones and mortar specimens while it was changed from 65 mm (corresponding to one stone and one mortar joint) to 195 mm (three stones and three mortar joints) in the case of masonry prisms. The effect of the FRP end anchorage on the test development was investigated as well, and results of the experimental tests are herein discussed in detail.

scholarly journals CAE Modeling Rubber-metal Body Mounting of the Body-on-frame Car in Crash Simulations

2020 ◽  
Vol 14 ◽  
Keyword(s):  
Impact Test ◽  
Point Of View ◽  
The Body ◽  
Crash Test ◽  
Test Results ◽  
Rigid Connection ◽  
Metal Body ◽  
Stiffness Characteristics ◽  
The Impact ◽  
Crash Tests

The aim of the study was to research the behavior of the rubber-metal body mounting under various modeling options and to select the optimal, from the point of view of ensuring the accuracy of the results in the crash tests simulations. Body supports provide a link between the body and the car frame, and this has a critical effect on the impact test results of the car. The article discusses various options for modeling the body mounting by the degree of simplification from the simplest model with a rigid connection between the body and the frame to the model that takes into account the non-linearity of the stiffness characteristics of the supports, contact interaction between parts of the mounting and its surrounding parts, tension of the supports and failure. The results of virtual tests of a car with various options for modeling mountings were compared with the results of real tests. As a result of the study, a methodology for modeling the body supports was developed, which allows providing the necessary measurement error in virtual crash test modeling.

scholarly journals ANALYSIS OF THE IMPACT OF ROAD SAFETY BARRIERS ON REDUCING THE RISK OF DANGEROUS ROAD ACCIDENTS AND THEIR CONSEQUENCES

2020 ◽  
Vol 1 (46) ◽  
pp. 283-292
Author(s):  
Savostin-Kosiak D ◽  
◽  
Michalski Jacek ◽  
Keyword(s):  
Test Methods ◽  
Design Methods ◽  
Point Of View ◽  
The Road ◽  
Road Signs ◽  
Safety Barriers ◽  
Road Systems ◽  
Functional Features ◽  
Aided Design ◽  
The Impact

The weaknesses of the road systems were analyzed, including dangerous events generated by vehicle getting out of the road and consequent secondary dangerous events such as: driving over a barrier or other dangerous object located next to road or roofing of the vehicle. Particularly, the security, availability of technological solutions for protection barriers, columns and road signs on roads and bridges were considered. The preventive and protective functions of road equipment and engineering objects are given, which are adequate to the specific risk. Failures of safety barriers and road protection barriers and the consequences of their failures for people, properties and the environment were analyzed. Solutions for the construction of road barriers were analyzed in terms of: availability, the degree of reliability of their components and the possibility of maintaining risk within acceptable limits. The scope of fulfillment of required functional features, design methods, modern technological solutions, test methods and certification procedures were analyzed. Functional features of protective barriers regarding: the protection level, displacements and the level of impact intensity were taken into account. Literature point of view on aided design of protective barriers has been included which covers finite element method (method of sum of displacements) with appropriate analysis of forces, torques and displacements with CAD systems including use of LS-DYNA system for events and damage parameters. A large part of the publication deals with modern technological solutions and analyzes including design of protective barriers, modeling of their elements as well as modeling collisions with vehicles, taking into account the impact of the ground. KEYWORDS: PROTECTION BARRIERS, FAILURES OF PROTECTION BARRIERS, DESIGN METHODS, SECURITY OF PROTECTION BARRIERS

Lost in calibration: why people still do not calibrate their models, and why they still should – a case study from urban drainage modelling

2016 ◽  
Vol 74 (10) ◽  
pp. 2337-2348 ◽  
Author(s):  
Franz Tscheikner-Gratl ◽  
Peter Zeisl ◽  
Carolina Kinzel ◽  
Johannes Leimgruber ◽  
Thomas Ertl ◽  
...  
Keyword(s):  
Model Calibration ◽  
Numerical Models ◽  
Point Of View ◽  
Engineering Practice ◽  
Storm Events ◽  
Large Cities ◽  
Design Storm ◽  
Actual Design ◽  
Design Values ◽  
The Impact

From a scientific point of view, it is unquestioned that numerical models for technical systems need to be calibrated. However, in sufficiently calibrated models are still used in engineering practice. Case studies in the scientific literature that deal with urban water management are mostly large cities, while little attention is paid to the differing boundary conditions of smaller municipalities. Consequently, the aim of this paper is to discuss the calibration of a hydrodynamic model of a small municipality (15,000 inhabitants). To represent the spatial distribution of precipitation, three distributed rain gauges were used for model calibration. To show the uncertainties imminent to the calibration process, 17 scenarios, differing in assumptions for calibration, were distinguished. To compare the impact of the different calibration scenarios on actual design values, design rainfall events were applied. The comparison of the model results using the different typical design storm events from all the surrounding data points showed substantial differences for the assessment of the sewers regarding urban flooding, emphasizing the necessity of uncertainty analysis for hydrodynamic models. Furthermore, model calibration is of the utmost importance, because uncalibrated models tend to overestimate flooding volume and therefore result in larger diameters and retention volumes.

scholarly journals Impact of Hydrogen Injection on Natural Gas Measurement

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8461
Author(s):  
Marco Dell’Isola ◽  
Giorgio Ficco ◽  
Linda Moretti ◽  
Jacek Jaworski ◽  
Paweł Kułaga ◽  
...  
Keyword(s):  
Natural Gas ◽  
Thermodynamic Properties ◽  
Calorific Value ◽  
Experimental Tests ◽  
Point Of View ◽  
Experimental Point ◽  
Theoretical Point ◽  
Primary Role ◽  
Gas Measurements ◽  
The Impact

Hydrogen is increasingly receiving a primary role as an energy vector in ensuring the achievement of the European decarbonization goals by 2050. In fact, Hydrogen could be produced also by electrolysis of water using renewable sources, such as photovoltaic and wind power, being able to perform the energy storage function, as well as through injection into natural gas infrastructures. However, hydrogen injection directly impacts thermodynamic properties of the gas itself, such as density, calorific value, Wobbe index, sound speed, etc. Consequently, this practice leads to changes in metrological behavior, especially in terms of volume and gas quality measurements. In this paper, the authors present an overview on the impact of hydrogen injection in natural gas measurements. In particular, the changes in thermodynamic properties of the gas mixtures with different H2 contents have been evaluated and the effects on the accuracy of volume conversion at standard conditions have been investigated both on the theoretical point of view and experimentally. To this end, the authors present and discuss the effect of H2 injection in gas networks on static ultrasonic domestic gas meters, both from a theoretical and an experimental point of view. Experimental tests demonstrated that ultrasonic gas meters are not significantly affected by H2 injection up to about 10%.

scholarly journals Structural Response and Stochastic Impact Modeling

2018 ◽  
Vol 183 ◽  
pp. 01050
Author(s):  
Renata Troian ◽  
Manel Dallali ◽  
Didier Lemosse ◽  
Leila Khalij
Keyword(s):  
Structural Model ◽  
Numerical Models ◽  
Structural Response ◽  
Point Of View ◽  
Structural Behavior ◽  
Beam Model ◽  
Wide Range ◽  
Extreme Sensitivity ◽  
The Impact ◽  
Bernoulli Beam Model

The problem of the vulnerability of structures facing explosions came to the front line of the scientific scene in the last decades. Uncertainty of the environmental conditions and material properties have to be taken into account. The corresponding numerical models are very complex and depend on numerous parameters. Consequently, such models are cursed with issues which limit their use for real applications. Most of the existing approaches are based on a deterministic point of view, and are not able to represent the extreme sensitivity of a model towards uncertain parameters. That is why the uncertainty analysis is needed. The proposed research is devoted to the analysis of a structural behavior under an uncertain impact loading. Elasto-plastic Bernoulli beam model is used as structural model for the case simplicity, while the different formulation for impact itself are studied to simulate the wide range of possible types of impact. Model sensitivity is studied first. The influence of input parameters on structural behavior, that are the impact force, duration and position, as well as beam material are then considered. The obtained insights can provide the guidelines for modeling the structure under the explosive loading taking into account the uncertainties.

scholarly journals Analysis of the Impact Dynamics of Shape Memory Alloy Hybrid Composites for Advanced Applications

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 153 ◽  
Author(s):  
Michele Guida ◽  
Andrea Sellitto ◽  
Francesco Marulo ◽  
Aniello Riccio
Keyword(s):  
Shape Memory Alloy ◽  
Carbon Fibre ◽  
Shape Memory ◽  
Hybrid Composites ◽  
Numerical Models ◽  
Experimental Tests ◽  
Lower Velocity ◽  
Reinforced Plastic ◽  
Carbon Fibre Reinforced Plastic ◽  
The Impact

In this work, the behaviour of thermoplastic composites and Shape Memory Alloy Hybrid Composites (SMAHCs) for aeronautical applications is analysed and compared by means of findings from numerical analyses and experimental tests. At first, experimental tests are performed by using a drop tower facility on both carbon fibre reinforced plastic samples and Carbon Fibre Reinforced Plastic (CFRP) samples hybridized with shape memory alloy materials. The materials properties and the different lower velocity impacts behaviours are simulated and validated by means of numerical models discretized in LS-Dyna explicit solver. For both configurations, the deformation mechanism for low intensity impacts, the absorbed energy, and the effect of rebounding upon the velocity change, and hence the amount of force, are investigated. Then, a configuration is prepared to withstand higher-energy impacts. Finally, the numerical analysis is extended for an innovative layup adapted on an aeronautical structure, which is subjected to the bird-strike phenomenon at 180 m/s and with an impacting mass of 1.8 kg according to the airworthiness requirements. In this study, SMAHCs are used to improve the composite impact response and energy absorption thanks to the superelastic effect.

Reverse Engineering of Experimental Tests Results of Ballistic Impact for the Validation of Finite Element Simulations

2010 ◽  
Author(s):  
Andrea Manes ◽  
Grazia Magrassi ◽  
Marco Giglio ◽  
Monica Bordegoni
Keyword(s):  
Finite Element ◽  
Reverse Engineering ◽  
Numerical Models ◽  
Real Data ◽  
Experimental Tests ◽  
Engineering Practice ◽  
Explicit Finite Element ◽  
3D Acquisition ◽  
Set Up ◽  
The Impact

In this paper the set up and the carrying out of experimental ballistic tests on a tail rotor transmission shafts for helicopter, which are impacted by a 7.62 NATO projectile, are presented. After the tests, a 3D acquisition of the impacted area on each shaft has been performed in order to acquire exactly the shape of the damage. The acquisition has been carried out with a 3D range camera. The experimental activities have been compared with the results of a numerical simulation of the impact, which has been computed with an explicit finite element code. The direct comparison has been done by superimposing the two meshes (from FE analysis and from 3D acquisition). This method has proved to be effective for identifying analogies and differences and for giving the possibility to promote a “quantitative” discussion with the aim of improving the accuracy of the numerical models and simulation conditions. The adoption of the Reverse Engineering practice has proved to be a powerful method for integrating and comparing the simulation data with real data, and give suggestions to further analysis.

Protection Effect on a Ballistic Impact of NATO 7.62 Ball Bullet into Helicopter Drive Shaft: Numerical Simulation

2011 ◽  
Vol 82 ◽  
pp. 710-715 ◽  
Author(s):  
Davide Lumassi ◽  
Andrea Manes ◽  
Marco Giglio
Keyword(s):  
Finite Element ◽  
Power Transmission ◽  
Numerical Models ◽  
Deformable Body ◽  
Numerical Procedure ◽  
Experimental Tests ◽  
Ballistic Impact ◽  
Drive Shaft ◽  
Constitutive Law ◽  
The Impact

Actual strategies and rules in peace keeping mission have led to an intensive use of helicopters exposing the aircraft and the crew to significant risks. Typical missions in fact involve low altitude flights in hostile environment where many threats can cause severe damages, leading eventually to the loss of the machine and the crew. According to this scenario, the tail rotor power transmission is one of the most critical components for its fundamental role to ensure flight stability and for its vulnerability, being very exposed during flight manoeuvre. In addition light weapons are wide spread, due to their cheapness and manoeuvrability. So the impact of 7.62x61 NATO ball 9.5 g bullet is an event anything but remote. This projectile is a full metal jacket bullet, with a brass jacket and a lead alloy core. Due to its mechanical characteristics, the soft lead core undergoes to high deformations and failures (mushroom and debris) during the impact, causing a large and extensive damaged area. Several researches have been developed to investigate the ballistic impact of conventional bullet against typical thin and lightweight aeronautical structure. As usual in this field, a complete methodology with experimental tests and numerical approaches has been carried on. In particular Finite Element analyses, although require complicate calibrations and validation which can be only made through indispensable experimental tests, represent a key resource. Very detailed numerical models are an extremely powerful tool to investigate the damage generated during an impact and allow simulating complex and extreme cases. With this premises direct impact between a 7.62x51 NATO ball 9.5 g bullet with a tube simulating an Helicopter drive shaft has been investigated by the authors in a previous work both with experimental and numerical activities with good agreement. However, considering the huge effect of bullet deformation verified during this activity, the modification of the bullet due to a preliminary impact with the surrounding frame (around the shaft in the real helicopter) could influence in a remarkable way the damage shape and extension in the shaft. This is an issue that is worth to further investigation and this is the aim of this paper. Basing only on a numerical procedure, previously assessed, an investigation of the impact of a NATO 7.62x51 mm ball 9.5 g bullet into an Al-6061-T6 pipe and its protection is presented. In particular the work will focus on the influence of the frame panel, which covers the transmission shaft, on the impact conditions. Analysis are carried out using the Finite Element commercial code ABAQUS/Explicit. Advanced materials’ descriptions, constitutive law and fracture criterion are introduced within the numerical model of the shaft and protection; projectile has been modelled as deformable body. Different impact conditions have also been tested in order to identify the worst impact condition.

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