scholarly journals Experimental and FE Study on Impact Strength of Toughened Glass–Retrospective Approach

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7658
Author(s):  
Marcin Kozłowski ◽  
Kinga Zemła ◽  
Magda Kosmal ◽  
Ołeksij Kopyłow
Keyword(s):  
Numerical Models ◽  
Peak Stress ◽  
Impact Loads ◽  
Toughened Glass ◽  
Load Duration ◽  
Wide Range ◽  
Modelling Methodology ◽  
Glass Panels ◽  
Set Up ◽  
The Impact

Due to the high cost of experiments commonly performed to verify the resistance of glass elements to impact loads, numerical models are used as an alternative to physical testing. In these, accurate material parameters are crucial for a realistic prediction of the behaviour of glass panels subjected to impact loads. This applies in particular to the glass’s strength, which is strictly dependent on the strain rate. The article reports the results of an extensive experimental campaign, in which 185 simply supported toughened glass samples were subjected to hard-body impacts. The study covers a wide range of glass thicknesses (from 5 to 15 mm), and it aims to determine a critical drop height causing fracture of the glass. Moreover, a 3D numerical model of the experimental set-up was developed to reproduce the experiments numerically and retrospectively to determine the peak stress in glass that developed during the impact. Based on the results of numerical simulations, a load duration factor of 1.40 for toughened glass for impact loads is proposed. In addition, the paper includes a case study to demonstrate the use of the modelling methodology and results of the work on a practical example of an internal glass partition wall.

Laser Forming of Metal Foam Sandwich Panels: Effect of Panel Manufacturing Method

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Tizian Bucher ◽  
Min Zhang ◽  
Chang Jun Chen ◽  
Ravi Verma ◽  
Wayne Li ◽  
...  
Keyword(s):  
Metal Foam ◽  
Numerical Models ◽  
Sandwich Panels ◽  
Weight Ratio ◽  
Industrial Applications ◽  
Laser Forming ◽  
Process Conditions ◽  
Foam Core ◽  
Wide Range ◽  
The Impact

Sandwich panels with metal foam cores have a tremendous potential in various industrial applications due to their outstanding strength-to-weight ratio, stiffness, and shock absorption capacity. A recent study paved the road toward a more economical implementation of sandwich panels, by showing that the material can be successfully bent up to large angles using laser forming. The study also developed a fundamental understanding of the underlying bending mechanisms and established accurate numerical models. In this study, these efforts were carried further, and the impact of the foam core structure, the facesheet and foam core compositions, and the adhesion method on the bending efficiency and the bending limit was investigated. These factors were studied individually and collectively by comparing two fundamentally different sandwich panel types. Thermally induced stresses at the facesheet/core interface were thoroughly considered. Numerical modeling was carried out under different levels of geometric accuracy to complement bending experiments under a wide range of process conditions. Interactions between panel properties and process conditions were demonstrated and discussed.

An Experimental Investigation of Wave Impact Loads on a Slender Horizontal Cylinder

2014 ◽  
Author(s):  
Joseph F. Haley ◽  
Chris Swan ◽  
Richard Gibson
Keyword(s):  
Water Surface ◽  
Impact Load ◽  
Horizontal Cylinder ◽  
The Body ◽  
Impact Loads ◽  
Wave Impact ◽  
Wide Range ◽  
Wave Event ◽  
Vector Sum ◽  
The Impact

This paper concerns the difficulties arising in the prediction of the impact loads associated with an extreme wave event. A new set of experimental observations are presented. These concern the impact loads arising on a slender horizontal cylinder located at varying elevations above the still water level. The experimental observations incorporate a wide range of wave forms. In each case, data is provided describing (i) the incident water surface profiles, (ii) the incident fluid velocities and (iii) the load components acting on the cylinder. Comparisons between the measured data and the classical impact load solutions confirm a number of important departures. In particular, it is shown that as the wave becomes very steep (approaching the breaking limit) the vector sum of the horizontal and vertical velocity components at the water surface may deviate significantly from the normal to the local water surface. In such cases it becomes unclear exactly what direction the impact force acts. The present data suggests that this is, in part, dependent on the rate of inundation of the body. Furthermore, the present results also show that if the direction of the force is correct modelled, the variations in the predicted loading (or slamming) coefficient are much reduced.

The Effect of SAS Materials and Modeling in Transferring Impact Loads to the Brain

2010 ◽  
Author(s):  
Parisa Saboori ◽  
Ali Sadegh
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Brain Injuries ◽  
Impact Load ◽  
Compressive Load ◽  
Impact Loads ◽  
Modeling Methodology ◽  
Wide Range ◽  
The Impact ◽  
The Brain

While subarachnoid space (SAS) trabeculae play an important role in damping and reducing the relative movement of the brain with respect to the skull, thereby reducing traumatic brain injuries, their mechanical properties and modeling are not well established in the literature. A few studies, e.g., Zhang et al. (2002) and Xin Jin et al. (2008) have reported a wide range the elastic modulus of the trabeculae up to three orders of magnitudes. The histology of the trabeculae reveals a collagen based structure. Thus, a few investigators have estimated the mechanical properties of trabeculae based on collagen’s properties. The objective of this study is to determine the stress/strain changes in the brain as a function of the mechanical properties and modeling methodology of the trabeculae, when the loading and the boundary conditions of the model are kept the same. This study was performed through several modeling steps. A wide range of the mechanical properties of the trabeculae was employed and the transductions of blunt impact loads from the skull to the brain were determined. The mechanical properties of the SAS trabeculae were determined based on the validation of the models with experimental results of Sabet et al. (2009). The result indicated that when we use softer material properties for the trabeculae the meningeal layers absorb and damp the impact load. It is also concluded that the material properties of the trabeculae can be simulated by only tension element since the trabeculae buckles with minimal compressive load. Finally, an optimum material property of SAS was proposed.

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 A review of the risk margin – Solvency II and beyond

2020 ◽  
Vol 25 ◽  
Author(s):  
A. J. Pelkiewicz ◽  
S. W. Ahmed ◽  
P. Fulcher ◽  
K. L. Johnson ◽  
S. M. Reynolds ◽  
...  
Keyword(s):  
Cost Of Capital ◽  
Working Party ◽  
Solvency Ii ◽  
Risk Margin ◽  
Life Insurers ◽  
Wide Range ◽  
The Difference ◽  
Set Up ◽  
The Uk ◽  
The Impact

Abstract For life insurers in the United Kingdom (UK), the risk margin is one of the most controversial aspects of the Solvency II regime which came into force in 2016. The risk margin is the difference between the technical provisions and the best estimate liabilities. The technical provisions are intended to be market-consistent, and so are defined as the amount required to be paid to transfer the business to another undertaking. In practice, the technical provisions cannot be directly calculated, and so the risk margin must be determined using a proxy method; the method chosen for Solvency II is known as the cost-of-capital method. Following the implementation of Solvency II, the risk margin came under considerable criticism for being too large and too sensitive to interest rate movements. These criticisms are particularly valid for annuity business in the UK – such business is of great significance to the system for retirement provision. A further criticism is that mitigation of the impact of the risk margin has led to an increase in reinsurance of longevity risks, particularly to overseas reinsurers. This criticism has led to political interest, and the risk margin was a major element of the Treasury Committee inquiry into EU Insurance Regulation. The working party was set up in response to this criticism. Our brief is to consider both the overall purpose of the risk margin for life insurers and solutions to the current problems, having regard to the possibility of post-Brexit flexibility. We have concluded that a risk margin in some form is necessary, although its size depends on the level of security desired, and so is primarily a political question. We have reviewed possible alternatives to the current risk margin, both within the existing cost-of-capital methodology and considering a wide range of alternatives. We believe that requirements for the risk margin will depend on future circumstances, in particular relating to Brexit, and we have identified a number of possible changes to methodology which should be considered, depending on circumstances.

Dynamic Analysis of Large Specialty Glass Panels Under Ball Drop Impact — Numerical Modeling and Measurements

2012 ◽  
Author(s):  
Satish C. Chaparala ◽  
Praveen R. Samala ◽  
Joshua M. Jacobs ◽  
Jonathan D. Pesansky
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Impact Energy ◽  
Consumer Electronics ◽  
Impact Loads ◽  
Cover Glass ◽  
Element Analysis ◽  
Glass Panels ◽  
Alumino Silicate ◽  
The Impact

Response of brittle plate-like structures to impact loads (suddenly applied loads) has been the subject of many research studies. Specifically, glass used in various household, consumer electronics applications can be subjected to different kinds of impact loads. An ion-exchanged alumino-silicate glass developed by Corning Incorporated, also called Corning® Gorilla® Glass is used as cover glass for flat-panel televisions. One of the reliability tests that may be required for this application is that a steel ball of certain diameter is dropped from certain height at different locations on the glass panel mounted onto a frame. The requirement is that the glass should survive 2 J of impact energy at the center of the glass and 0.5 J of impact energy at the edges. These reliability requirements could change depending on the application and the customer. In this study, finite element analysis is carried out to understand the impact response of such glass panels. Experiments are conducted using strain gauges to measure the panel response at the center of glass with impacts up to 3.3 J. Finite element analysis results are then validated by comparing the predicted strain response with those of measurements.

scholarly journals Explicit Dynamic Analysis by a Rigid Body-Spring Model of Impact Loads of Artillery on Middle Age Fortifications

Buildings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 607
Author(s):  
Vito Tateo ◽  
Siro Casolo
Keyword(s):  
Rigid Body ◽  
Middle Ages ◽  
Architectural Design ◽  
Inner Core ◽  
Middle Age ◽  
Numerical Models ◽  
Impact Loads ◽  
Spring Model ◽  
Explicit Dynamic ◽  
The Impact

The development of artillery in Europe at the end of the Middle Ages brought a necessary change in military architecture. This change was a radical rethinking of the entire geometry and architectural design of city walls which required an increase in thickness to resist repeated artillery strikes. The damage due to the impact loads on Middle Age fortification walls is analyzed herein with explicit dynamic analyses. This study was developed both with finite element models and an innovative rigid body-spring model with diagonal springs (RBSM), showing the different peculiarities of these two different approaches and how their results can be integrated. The numerical models clearly showed that the presence of an inner core of softer material tends to modify the impact effects by reducing the degree of damage at the expense of an extension of the damaged area.

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.

Laser Forming of Metal Foam Sandwich Panels: Effect of Panel Manufacturing Method

2019 ◽  
Author(s):  
Tizian Bucher ◽  
Min Zhang ◽  
Chang Jun Chen ◽  
Ravi Verma ◽  
Wayne Li ◽  
...  
Keyword(s):  
Metal Foam ◽  
Numerical Models ◽  
Sandwich Panels ◽  
Weight Ratio ◽  
Industrial Applications ◽  
Laser Forming ◽  
Process Conditions ◽  
Foam Core ◽  
Wide Range ◽  
The Impact

Abstract Sandwich panels with metal foam cores have a tremendous potential in various industrial applications due to their outstanding strength-to-weight ratio, stiffness, and shock absorption capacity. A recent study paved the road towards a more economical implementation of sandwich panels, by showing that the material can be successfully bent up to large angles using laser forming. The study also developed a fundamental understanding of the underlying bending mechanisms and established accurate numerical models. In this study, these efforts were carried further, and the impact of the foam core structure, the facesheet and foam core compositions, as well as the adhesion method on the bending efficiency and bending limit was investigated. These factors were studied individually and collectively by comparing two fundamentally different sandwich panel types. Thermally-induced stresses at the facesheet/core interface were thoroughly considered. Numerical modeling was carried out under different levels of geometric accuracy, to complement bending experiments under a wide range of process conditions. Interactions between panel properties and process conditions were demonstrated and discussed.

scholarly journals Parton distributions with theory uncertainties: general formalism and first phenomenological studies

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Rabah Abdul Khalek ◽  
Richard D. Ball ◽  
Stefano Carrazza ◽  
Stefano Forte ◽  
Tommaso Giani ◽  
...  
Keyword(s):  
Covariance Matrix ◽  
Cross Sections ◽  
Distribution Functions ◽  
Matrix Formalism ◽  
Parton Distribution Functions ◽  
Central Values ◽  
Wide Range ◽  
Algebraic Framework ◽  
Set Up ◽  
The Impact

AbstractWe formulate a general approach to the inclusion of theoretical uncertainties, specifically those related to the missing higher order uncertainty (MHOU), in the determination of parton distribution functions (PDFs). We demonstrate how, under quite generic assumptions, theory uncertainties can be included as an extra contribution to the covariance matrix when determining PDFs from data. We then review, clarify, and systematize the use of renormalization and factorization scale variations as a means to estimate MHOUs consistently in deep inelastic and hadronic processes. We define a set of prescriptions for constructing a theory covariance matrix using scale variations, which can be used in global fits of data from a wide range of different processes, based on choosing a set of independent scale variations suitably correlated within and across processes. We set up an algebraic framework for the choice and validation of an optimal prescription by comparing the estimate of MHOU encoded in the next-to-leading order (NLO) theory covariance matrix to the observed shifts between NLO and NNLO predictions. We perform a NLO PDF determination which includes the MHOU, assess the impact of the inclusion of MHOUs on the PDF central values and uncertainties, and validate the results by comparison to the known shift between NLO and NNLO PDFs. We finally study the impact of the inclusion of MHOUs in a global PDF determination on LHC cross-sections, and provide guidelines for their use in precision phenomenology. In addition, we also compare the results based on the theory covariance matrix formalism to those obtained by performing PDF determinations based on different scale choices.

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