scholarly journals The Compressive Behavior and Crashworthiness of Cork: A Review

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 134
Author(s):  
Claudia Sergi ◽  
Fabrizio Sarasini ◽  
Jacopo Tirillò
Keyword(s):  
Industrial Applications ◽  
Core Material ◽  
Design Parameters ◽  
Natural State ◽  
Complex Nature ◽  
Natural Material ◽  
Compressive Behavior ◽  
Compressive Response ◽  
The Right ◽  
Energy Absorbing

Cork, a natural material from renewable resources, is currently attracting increasing interest in different industrial fields because of its cellular structure and the presence of the flexible suberin as its main chemical component. In an agglomerated form, it proved to be a compelling product not only as a thermal and acoustic insulator, but also as core material in sandwich structures and as a liner or padding in energy absorbing equipment. From this perspective, the assessment of its compressive response is fundamental to ensure the right out-of-plane stiffness required to a core material and the proper crashworthiness in the safety devices. Considering the complex nature of cork and the resulting peculiar compressive response, the present review article provides an overview of this paramount property, assessing the main parameters (anisotropy, temperature, strain rate, etc.) and the peculiar features (near-zero Poisson’s ratio and unique dimensional recovery) that characterize it in its natural state. Furthermore, considering its massive exploitation in the agglomerated form, the design parameters that allow its compressive behavior to be tailored and the operating parameters that can affect its crashworthiness were assessed, reporting some potential industrial applications.

Crashworthiness Challenges in Steel-to-Aluminum Front End Design

2002 ◽  
Author(s):  
Mohamed R. Baccouche ◽  
David A. Wagner ◽  
Hikmat F. Mahmood ◽  
Ismail O. Yaman
Keyword(s):  
Energy Management ◽  
Specific Energy ◽  
Design Parameters ◽  
Corporate Average Fuel Economy ◽  
Design Load ◽  
Management Efficiency ◽  
Aluminum Sheets ◽  
Front End ◽  
The Right ◽  
Energy Absorbing

The search for weight reduction opportunities to improve corporate average fuel economy has led the auto industry to investigate light weight materials such as aluminum and magnesium. These materials can reduce vehicle weight while satisfying crash safety requirements of corporate, government, and independent insurance agencies. As a result, designs of several vehicles have been fully migrated from steel to aluminum while many other vehicles have opted to substitute lighter materials at the component and system levels. An investigation has been conducted on the front end principal crash energy absorbing rails to convert the original HSLA350 steel structural members into 5754NG aluminum. The investigation shows that while the substitution of aluminum at the right thickness can achieve lighter weight and higher specific energy, additional design parameters such as design load targets remain a major challenge. A comparison of steel versus aluminum mean crash loads, crash energy management, weight saved, specific energy, and design load target highlights some of these challenges. The results from an experimental investigation of stamped 5754NG aluminum sheet rails show the substitution of stamped 5754NG aluminum sheets for steel rails reduces the weight of each of the front rails by 3.3 (lb) and enhances the specific crash energy management efficiency by 38%. To solve the design load target challenge, the same investigation extends to higher strength 6xxx series extruded aluminum material using CAE modeling and demonstrates an increase in crash energy management efficiency of up to 80%.

The influence of confocal microscope design on imaging performance

1993 ◽  
Vol 51 ◽  
pp. 144-145
Author(s):  
C J R Sheppard
Keyword(s):  
Image Quality ◽  
Fluorescence Imaging ◽  
Confocal Microscope ◽  
Industrial Applications ◽  
Three Dimensions ◽  
Design Parameters ◽  
Weak Signals ◽  
Size And Shape ◽  
Imaging Performance ◽  
Fundamental Limitation

The confocal microscope is now widely used in both biomedical and industrial applications for imaging, in three dimensions, objects with appreciable depth. There are now a range of different microscopes on the market, which have adopted a variety of different designs. The aim of this paper is to explore the effects on imaging performance of design parameters including the method of scanning, the type of detector, and the size and shape of the confocal aperture.It is becoming apparent that there is no such thing as an ideal confocal microscope: all systems have limitations and the best compromise depends on what the microscope is used for and how it is used. The most important compromise at present is between image quality and speed of scanning, which is particularly apparent when imaging with very weak signals. If great speed is not of importance, then the fundamental limitation for fluorescence imaging is the detection of sufficient numbers of photons before the fluorochrome bleaches.

Low Velocity Impact Response of Composite/Sandwich Structures

2016 ◽  
Vol 725 ◽  
pp. 127-131 ◽  
Author(s):  
Kumar V. Akshaj ◽  
P. Surya ◽  
M.K. Pandit
Keyword(s):  
Sandwich Structures ◽  
Weight Ratio ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Core Material ◽  
Design Parameters ◽  
Low Velocity ◽  
Velocity Impact ◽  
Composite Sandwich ◽  
Set Up

Dent resistance of structures is one of the important design parameters to consider in automotive, aerospace, packaging and transportation of fragile goods, civil engineering and marine industries. It is important to study the dynamic impact response of various combinations of skin and core materials which can provide desired fracture toughness and highest strength to weight ratio for such applications. This paper discusses the low velocity impact response of sandwich structures having unique combination of mild steel as skin material bonded to thermoplastics/PU foam as core material. HDPE, LDPE and polypropylene were the choice of thermoplastics and an optimum combination of materials for the sandwich structure was evaluated using drop-weight experimental set up. It is observed that LDPE is the best choice of core material for the sandwich structures considered.

Development of an End-Effector for Mitigation of Collisions

2021 ◽  
Author(s):  
Domenico Tommasino ◽  
Matteo Bottin ◽  
Giulio Cipriani ◽  
Alberto Doria ◽  
Giulio Rosati
Keyword(s):  
Numerical Simulations ◽  
Industrial Applications ◽  
Operating Conditions ◽  
Contact Forces ◽  
Design Parameters ◽  
End Effector ◽  
Linear Behavior ◽  
Stable Mechanism ◽  
Robot Tasks ◽  
The Impact

Abstract In robotics the risk of collisions is present both in industrial applications and in remote handling. If a collision occurs, the impact may damage both the robot and external equipment, which may result in successive imprecise robot tasks or line stops, reducing robot efficiency. As a result, appropriate collision avoidance algorithms should be used or, if it is not possible, the robot must be able to react to impacts reducing the contact forces. For this purpose, this paper focuses on the development of a special end-effector that can withstand impacts and is able to protect the robot from impulsive forces. The novel end-effector is based on a bi-stable mechanism that decouples the dynamics of the end-effector from the dynamics of the robot. The intrinsically non-linear behavior of the end-effector is investigated with the aid of numerical simulations. The effect of design parameters and the operating conditions are analyzed and the interaction between the functioning of the bi-stable mechanism and the control system is studied. In particular, the effect of the mechanism in different scenarios characterized by different robot velocities is shown. Results of numerical simulations assess the validity of the proposed end-effector, which can lead to large reductions in impact forces.

scholarly journals A simulation-based approach to improve decoded neurofeedback performance

2018 ◽  
Author(s):  
Ethan Oblak ◽  
James Sulzer ◽  
Jarrod Lewis-Peacock
Keyword(s):  
Real Time ◽  
Brain Activity ◽  
Processing Parameters ◽  
Orientation Tuning ◽  
Design Parameters ◽  
Visual Orientation ◽  
Brain Functions ◽  
Simulation Based ◽  
Using Data ◽  
The Right

AbstractThe neural correlates of specific brain functions such as visual orientation tuning and individual finger movements can be revealed using multivoxel pattern analysis (MVPA) of fMRI data. Neurofeedback based on these distributed patterns of brain activity presents a unique ability for precise neuromodulation. Recent applications of this technique, known as decoded neurofeedback, have manipulated fear conditioning, visual perception, confidence judgements and facial preference. However, there has yet to be an empirical justification of the timing and data processing parameters of these experiments. Suboptimal parameter settings could impact the efficacy of neurofeedback learning and contribute to the ‘non-responder’ effect. The goal of this study was to investigate how design parameters of decoded neurofeedback experiments affect decoding accuracy and neurofeedback performance. Subjects participated in three fMRI sessions: two ‘finger localizer’ sessions to identify the fMRI patterns associated with each of the four fingers of the right hand, and one ‘finger finding’ neurofeedback session to assess neurofeedback performance. Using only the localizer data, we show that real-time decoding can be degraded by poor experiment timing or ROI selection. To set key parameters for the neurofeedback session, we used offline simulations of decoded neurofeedback using data from the localizer sessions to predict neurofeedback performance. We show that these predictions align with real neurofeedback performance at the group level and can also explain individual differences in neurofeedback success. Overall, this work demonstrates the usefulness of offline simulation to improve the success of real-time decoded neurofeedback experiments.

scholarly journals Assessing the Usability of Online Food Ordering Websites Using a New Fuzzy Kano Method: Implications for Improvement

2019 ◽  
Vol 14 (10) ◽  
pp. 87 ◽  
Author(s):  
Arshia Taimouri ◽  
Korosh Emamisaleh ◽  
Davoud Mohammadi
Keyword(s):  
Customer Satisfaction ◽  
Rapid Development ◽  
Complete Information ◽  
Study Data ◽  
Design Parameters ◽  
The Internet ◽  
High Quality ◽  
Essential Point ◽  
The Right ◽  
Important Design

Following the rapid development of the Internet, e-commerce websites are widely used today for various goals. An essential point in the prosperity of these websites is their level of usability. Accordingly, measuring this usability is indispensable for these websites to check whether they are moving in the right path. Thus, in this article, the usability scores of five well-known online food-ordering websites in Iran have been evaluated using a novel fuzzy Kano method with respect to design parameters. In addition to assessing usability scores, the design parameters of these websites have been classified and reviewed in a detailed manner in order to determine the design priorities of these websites as one of the main results of this study. Data were gathered using a questionnaire with 190 respondents. Results demonstrated that Snappfood is the best online food-ordering website in Iran. In addition, sorting restaurants based on customer satisfaction score, using high-quality images of foods along with the image zooming feature, and the existence of complete information about foods and restaurants are the most effective and important design parameters of these types of websites according to the findings of this study.

XV. Account of some experiments on the ascent of the sap in trees. In a letter from Thomas Andrew Knight, Esq. to the Right Hon. Sir Joseph Banks, Bart. K. B. P. R. S

1801 ◽  
Vol 91 ◽  
pp. 333-353 ◽  
Keyword(s):  
The Other ◽  
Natural State ◽  
The Right

My dear sir, The cause of the ascent of the sap in trees appearing to me not to have been satisfactorily accounted for, I have lately turned my attention to that subject; and, as some facts have come under my observation, which do not appear to have been noticed by any author that I have seen, I take the liberty to trouble you with an account of a few of the experiments that I have made; hoping that some of them may appear new and interesting to you. These experiments were made on different kinds of trees; but I shall confine myself to those made on the crab-tree, the horse-chesnut, the vine, and the oak; and shall begin with those made on the crab-tree. Choosing several young trees of this species in my nursery, of something more than half an inch diameter, and of equal vigour, I made two circular incisions through the bark, round one half the number of them, about half an inch distant from each other, early in the spring of 1799; and I totally removed the bark between these incisions, scraping off the external coat of the wood. The other half I left in their natural state.

The Effect of Wall Thermal Boundary Condition on Natural Convective Shutdown Cooling in a Gas Turbine

2021 ◽  
pp. 1-25
Author(s):  
Daniel Fahy ◽  
Peter Ireland
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Thermal Gradient ◽  
Low Cost ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Design Parameters ◽  
Complex Nature ◽  
Convective Boundary ◽  
Thermocouple Probe

Abstract As a civil gas turbine cools down, asymmetric natural convective heat transfer causes the bottom sector of the rotor to cool faster than the top; this circumferential thermal gradient can potentially cause the shaft to deflect – a phenomenon called thermal or rotor bow. Rotor bow is tremendously difficult to predict due to its dependence on a number of engine design parameters, in addition to the complex nature of natural convective flows. A novel experimental facility has been developed to gain further understanding into shutdown cooling of a gas turbine. The scope of this paper is to quantify the effect of basic design features on natural convective cooling in an engine annulus during shut-down. In addition to this, a low-cost, robust thermocouple probe has been developed and validated, which allows for accurate temperature measurements in a natural convective boundary layer. An extensive experimental campaign has been completed. The key finding is that the local radial wall temperature difference was found to be the most influential parameter on the local heat transfer. Non-isothermal walls did not alter the overall distribution of the inner wall equivalent conductivity. This was true for both cylindrical and conical sections. Therefore, the mean surface heat transfer for non-isothermal inner and outer profiles, within the range −0.4<Ra/RaLc <0.4, where the thermal gradient is negative in the clockwise from top-dead- centre, can be predicted using isothermal correlations for RaLc < 5.0 × 105 and Dr < = 1.5.

scholarly journals UUX Evaluation of a Digitally Advanced Human–Machine Interface for Excavators

2020 ◽  
Vol 4 (3) ◽  
pp. 57
Author(s):  
Sebastian Lorenz ◽  
Jens R. Helmert ◽  
Ruben Anders ◽  
Christian Wölfel ◽  
Jens Krzywinski
Keyword(s):  
User Experience ◽  
User Interfaces ◽  
Quality Measurement ◽  
Industrial Applications ◽  
Human Machine Interface ◽  
The Novel ◽  
Task Load ◽  
System Usability Scale ◽  
Machine Interface ◽  
The Right

With the evaluation of a next-generation human–machine interface (HMI) concept for excavators, this study aims to discuss the HMI quality measurement based on usability and user experience (UUX) metrics. Regarding the digital transformation of construction sites, future work environments will have to be capable of presenting various complex visual data and enabling efficient and safe interactivity while working. The evaluated HMI focused on introducing a touch display-based interface, providing advanced operation functions and different interaction modalities. The assessment of UUX should show whether the novel HMI can be utilised to perform typical tasks (usability) and how it is accepted and assessed in terms of non-instrumental qualities (user experience, UX). Using the collected data, this article also aims to contribute to the general discussion about the role of UX beyond usability in industrial applications and deepen the understanding of non-instrumental qualities when it comes to user-oriented process and machine design. The exploratory study examines insights into the application of elaborated UUX measuring tools like the User Experience Questionnaire (UEQ) on the interaction with industrial goods accompanied by their rating with other tools, namely System Usability Scale (SUS), Intuitive Interaction Questionnaire (INTUI) and the National Aeronautics and Space Administration (NASA) Task Load Index (NASA-TLX). Four goals are pursued in this study. The first goal is to compare in-depth two different ways of interaction with the novel HMI—namely one by a control pad on the right joystick and one by touch. Therefore, a sample of 17 subjects in total was split into two groups and differences in UUX measures were tested. Secondly, the performances of both groups were tested over the course of trials to investigate possible differences in detail. The third goal is to interpret measures of usability and user experience against existing benchmark values. Fourth and finally, we use the data gathered to analyse correlations between measures of UUX. The results of our study show that the different ways of interaction did not impact any of the measures taken. In terms of detailed performance analysis, both groups yielded differences in terms of time per action, but not between the groups. The comparison of UUX measures with benchmark values yielded mixed results. The UUX measures show some relevant significant correlations. The participants mostly reported enjoying the use of the HMI concept, but several practical issues (e.g., efficiency) still need to be overcome. Once again, the study confirms the urge of user inclusion in product development. Especially in the course of digitalisation, as big scale advancements of systems and user interfaces bring uncertainty for many manufacturers regarding whether or how a feature should be integrated.

scholarly journals Characterisation of Aluminium Matrix Syntactic Foams under Static and Dynamic Loading

2011 ◽  
Vol 82 ◽  
pp. 142-147 ◽  
Author(s):  
Mohamed Altenaiji ◽  
Graham K. Schleyer ◽  
Yo Yang Zhao
Keyword(s):  
Compressive Strength ◽  
Porous Ceramic ◽  
Syntactic Foam ◽  
Absorption Capacity ◽  
Core Material ◽  
Aluminium Matrix ◽  
Test Machine ◽  
Syntactic Foams ◽  
Pressure Infiltration ◽  
Energy Absorbing

Development of a lightweight, strong and energy-absorbing material that has potential application for the protection of vehicles and occupants against impact and blast, is a difficult challenge facing the materials community. Aluminium matrix syntactic foams will be investigated as a possible core material as part of a multi-layered protection system for military vehicles. Aluminium matrix syntactic foams are composite materials consisting of an aluminium matrix implanted with hollow or porous ceramic particles. This paper investigates the mechanical properties of aluminium matrix syntactic foam with different sizes of ceramic micro-spheres and different grades of aluminium, fabricated by the pressure infiltration method. The static crushing behaviour of the foam was investigated under two test conditions using an Instron 4505 machine. Results are compared and discussed. The dynamic compressive response was investigated using a drop-weight impact test machine. It was found that the particle size of the ceramic micro-spheres and the grade of the aluminium metal have a significant effect on the energy absorption capacity of the material. The compressive strength of the syntactic foam was found to increase with increasing compressive strength of the metal matrix.

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