Relevant Design Data Research Articles

A rapid evaluation method based on natural frequency for post-earthquake traffic capacity of small and medium span bridges

To improve the efficiency of evaluating the traffic capacity of bridges after the earthquake, a rapid method based on natural frequency for evaluating post-earthquake traffic capacity of small and medium-span bridges is proposed. Firstly, OpenSees software is selected to establish the seismic numerical analysis model of the pier, and the pressure of the main girder on the pier is equivalent to concentrated mass to extract the dynamic characteristics of the pier. The horizontal thrust on the pier top is adopted to simulate seismic action by the pseudo-static method, and the horizontal thrust is controlled by the maximum horizontal displacement. The value range of pier parameters is determined according to the definition of the regular bridge and relevant design data, then the design parameters and maximum horizontal displacement of each pier are sampled by the Latin hypercube sampling method to obtain various combined working conditions. Subsequently, the natural frequency, residual displacement and bearing capacity of the pier under different working conditions are obtained through numerical simulation. The relationship between natural frequency and residual bearing capacity of the pier after the earthquake is established in light of the simulation results of pier models. Then, the vehicle load is arranged on the basis of the most unfavorable loading principle, and the bearable maximum vehicle weight of the bridge is estimated from the bearing capacity of each pier, so that the traffic capacity of the bridge after the earthquake can be quickly evaluated by the change of natural frequency of piers. Finally, the reliability of the pier numerical model and residual displacement calculation method are verified by the test results of piers. The application process of the evaluation method proposed in this paper is illustrated by two typical examples of a simply supported beam bridge and a continuous beam bridge, which proves the feasibility of this method.

Lightweight Design and Additive Manufacturing of a Fatigue-Critical Automotive Component

<div class="section abstract"><div class="htmlview paragraph">Metal additive manufacturing is finding growing applicability in motorsports and high performance car sectors. Laser-Powder Bed Fusion (L-PBF) is the most developed AM technology for lightweight aluminum alloys producing near-net-shape components of complex geometry that achieve outstanding lightweight targets. A key issue in the widespread industrial acceptability of L-PBF is the structural integrity of these lightweight components when subjected to dynamic loading conditions because it requires in-depth knowledge of the fatigue behavior of L-PBF aluminum under the combined effect of stress gradients, residual stresses, surface condition and process-induced internal defects. This contribution overviews the presentation and application of an integrated design workflow that includes the following phases: i) a topological optimization phase to achieve lightweight targets, ii) a design for additive manufacturing phase supported by process simulation to optimize part production, iii) actual part fabrication in an industrial-grade L-PBF system using AlSi10Mg alloy powder followed by post fabrication heat treatment iv) production and fatigue testing of witness specimens providing relevant design data; v) fatigue testing of the parts to determine actual performance and vi) final assessment of the design know-how developed for fatigue-critical additively manufactured metal components.</div></div>

Ship Impact Force Analysis and Design Project Selection of Pinghai Bridge

Based on summing up the domestic and foreign ship impact force calculation formula, the finite element method was used to establish the Pinghai Bridge analysis model. The pier ship impact force as a reference came from relevant design data, and the finite element calculation and analysis on ship impact were carried out. For there is auxiliary pier and not, the internal forces of main pier, cap bottom of main pier and a single pile under the combinations of ship impact force along and across the bridge direction of Pinghai Bridge were respectively calculated and reinforcement designed. The results show that the section of main pier can meet the force requirements only by the structural reinforcement; under the ship impact loads, saving the auxiliary pier has little effect on the results of section reinforcement of the main tower and the main pier. These conclusions have reference values to some extent for the design plan selection under the action of ship impact force.

Smart Design on the Flexible Gear based on Knowledge Graph

The design of a mechanical component, such as flexible gear, would require plenty of time and energy retrieval relevant design data, information, and knowledge to complete the design tasks. However, current design support tools can hardly assist this requirement. To fill this gap, this paper has proposed a smart design tool based on knowledge graph to intelligent recommend the possible design data, information, and knowledge to engineering designs to facilitate their design tasks and improve design efficiency. This smart design method includes three parts, creating knowledge representation model, constructing knowledge graph, and developing collaborative knowledge management system for implementation. The methodology is demonstrated in this paper with a case study on the design of a double-arc tooth profile flexible gear for a harmonic drive reducer. The results have shown the feasibility of the method, the improvement in the design efficiency through intelligent recommendation of design data, information, and knowledge.

Current status and future perspectives of EU ceramic breeder development

• EU reference tritium breeding pebbles are produced using a melt-based process. • Process scale-up is underway to ensure the supply for ITER. • Biphasic materials show enhanced mechanical strength and stability. • Design relevant data were summarised in a material property handbook. • Crucial neutron irradiation experiments will complement the material qualification Biphasic ceramic pebbles, consisting of Li 4 SiO 4 and Li 2 TiO 3 , are being developed as the EU reference tritium breeding material for ITER and DEMO. A modified melt-based process for the pebble fabrication was established and optimised with regard to the process stability and yield. In parallel, the properties of pebbles and pebble beds were evaluated in dedicated experiments. These include investigations into e.g. the long-term thermal stability of pebbles, the thermomechanical properties of pebble beds, as well as the compatibility between the ceramics and the structural material. The available data was recently summarised and issued as the Material Property Handbook on Advanced Ceramic Breeders. During the EU DEMO conceptual phase, two main issues are proposed to be pursued in view of ITER. Irradiation campaigns are planned to ensure that the advanced ceramic breeder material is adequately tested and an extensive process scale-up with an increased production rate is foreseen to secure the supply for the ITER test blanket modules.

Deep learning-driven particle swarm optimisation for additive manufacturing energy optimisation

The additive manufacturing (AM) process is characterised as a high energy-consuming process, which has a significant impact on the environment and sustainability. The topic of AM energy consumption modelling, prediction, and optimisation has then become a research focus in both industry and academia. This issue involves many relevant features, such as material condition, process operation, part and process design, working environment, and so on. While existing studies reveal that AM energy consumption modelling largely depends on the design-relevant features in practice, it has not been given sufficient attention. Therefore, in this study, design-relevant features are firstly examined with respect to energy modelling. These features are typically determined by part designers and process operators before production. The AM energy consumption knowledge, hidden in the design-relevant features, is exploited for prediction modelling through a design-relevant data analytics approach. Based on the new modelling approach, a novel deep learning-driven particle swarm optimisation (DLD-PSO) method is proposed to optimise the energy utility. Deep learning is introduced to address several issues, in terms of increasing the search speed and enhancing the global best of PSO. Finally, using the design-relevant data collected from a real-world AM system in production, a case study is presented to validate the proposed modelling approach, and the results reveal its merits. Meanwhile, optimisation has also been carried out to guide part designers and process operators to revise their designs and decisions in order to reduce the energy consumption of the designated AM system under study.

Evaluation Of Construct Elicitation As A Research Method To Obtain Design-Relevant Data From Children

Understanding user requirements is a very important input in design process. Innovative designs derive from experiential and generative research methods in order to reveal tacit user knowledge instead of predicating on assumptions about the user. This is a more critical issue in design research with children. First of all, the way young users interact with products are different than that of adults. Second, user research methodologies devised for adult users fall short of meeting the needs of children, which effects reliability of data gathered during design research. A variety of research methodologies have been utilized to enable children better articulate the dimensions of their experience with products, as well as helping designers to have a better comprehension of user requirements. However; communication of gathered user knowledge with designers is also a challenging task. Designers need a holistic understanding of user space, and to be able to investigate the various dimensions and layers of user experience throughout design process. Hence, the need of a well-structured, child-friendly research methodology becomes evident for eliciting design-relevant data from young users. The aim of this study is to explore the potential of a construct elicitation method based on George Kelly’s ‘Repertory Grid Technique’ (RGT) in order to elicit design-relevant constructs from children. A study about perceived qualities of mobile phones was conducted with first grade and second grade primary school children (n=44) by utilizing a revised version of RGT in accordance with children’s needs as a tool to reveal personal constructs of children to inform design process. Results show that RGT is a useful tool for design researchers to gather information from children by demonstrating the relationship of product attributes and attached meanings, and models of user-product interaction in a multidimensional and multi-layered manner. Keywords: Design for children, design knowledge, repertory grid technique, user experience, user models

Inputs from in situ experiments to the understanding of the unsaturated behaviour of Callovo-Oxfordian claystone

The French national radioactive waste management agency (Andra) research program is dedicated to preparing the construction and operation of a deep geological disposal facility for high-level and intermediate-level long-lived radioactive waste (HL, IL-LLW) in the Callovo-Oxfordian claystone (COx). The characterization of the COx thermo-hydro-mechanical (THM) behavior, at different scales of interest, must gradually give relevant data for design and safety calculations. The effects of saturation and desaturation of COx claystone are studied in laboratory conditions (sample scale) and in situ (drift scale), in order to improve knowledge on ventilation effect at gallery wall as galleries will remains open during operational phase (more than 100 years for some specific galleries) in the repository. The Saturation Damaged Zone (SDZ) experiment is outlined and its results are discussed. This experimentation aims to change the relative humidity in an isolated portion of a gallery in order to follow the HM behavior of the surrounding rock mass. Drying and wetting cycles could induce in certain cases cracks and swelling and modify the hydromechanical behavior of the claystone around the gallery (Young modulus, strength, creep…). The long term behavior of the COx claystone at the vicinity of gallery is then studied by performing climatic, hydraulic, geological and geomechanical measurements. Results of the in situ experiment are discussed with respect to the identified process on samples. The discussion given on this paper intends to highlights the inputs from 7 years of an in situ experiment to better understand the unsaturated behavior of the COx claystone.

Internal Transport Coefficient Measurements in Random Fiber Matrix Heat Exchangers

Experimental determination of transport coefficients, in particular internal heat transfer coefficients, in heterogeneous and hierarchical heat transfer devices such as compact regenerative heat exchangers has posed a persistent challenge for designers. The goal of this study is to (1) present a new general treatment of the experimental determination of such design data, to (2) provide simple correlations for high porosity random fiber matrices for broad design applications, and to (3) illustrate how such measurements close the formidable integro-differential volume averaging theory (VAT) equations governing transport phenomena in porous media. The combined experimental and computational method employed here for determining the internal heat transfer coefficient in the porous structure is based on the VAT model and combines with simple pressure drop measurements to yield the relevant design data for eight different high porosity random fiber samples. The design data are correlated based on a porous media length scale derived from the VAT model governing equations and the transport coefficient correlations obtained are valid for gas flows over a Reynolds number range between 5 and 70. Finally, the correlations are related to explicit, rigorously derived, lower-scale expressions arising from the VAT model. With the illustration of a new experimental tool, and the production of new simple design correlations for high porosity random fiber matrices for regenerative heat transfer applications, within the context of the hierarchical VAT model, future VAT-based simulation studies of such devices may be pursued. Moreover, the nonlocal modeling provided by VAT paves the way to meaningful optimization studies due to its singular ability to provide rigorous modeling and fast numerical solutions for transport phenomena in regenerative compact heat exchangers.

Buckling analysis of a cylindrical shell, under neutron radiation environment

Abstract This research investigates the buckling of a cylindrical shell in the neutron radiation environment, subjected to combined static and periodic axial forces. Radiation induced porosity in elastic materials affects the thermal, electrical and mechanical properties of the materials. In this study, the data based technique was used to determine the volume fraction porosity, P , of shell material. A least-squares fit of the Young's module data yielded the estimated Young's modulus. The shell assumed made of iron irradiated in the range of 2–15e−7 dPa/s at 345–650 °C and theoretical formulations are presented based on the classical shell theory (CST). The research deals with the problem theoretically; keeping in mind that one means of generating relevant design data is to investigate prototype structures. A parametric study is followed and the stability of shell is discussed. It is concluded that both temperature and neutron induced swelling have significant effects on the buckling load.

A silicon nitride reference material—A testing program of ESIS TC6

Silicon nitrides with sufficient strength for structural applications have been developed 20 years ago. A break-through in the use of these ceramics for structural applications did not yet take place. Most probably, the reason for this is a significant lack of design relevant data. TC 6 “Ceramics” of the European Structural Integrity Society (ESIS) has established a research program in order to determine a complete set of material properties and data indispensable for design for a commercially available silicon nitride ceramic. The material chosen as the ESIS Silicon Nitride Reference Material is a gas pressure sintered silicon nitride containing ∼3 wt.% Al 2O 3 and ∼3 wt.% Y 2O 3. The results available to the present indicate that this specific material has a good mechanical performance at room temperature and up to ∼800 °C. Above this temperature the large amount of amorphous grain boundary phase causes a detrimental influence on the environmental assisted crack growth properties and the creep performance.

Intelligent Data Storage and Retrieval for Design Optimisation – an Overview

This paper documents the findings of a literature review conducted by the Sir Lawrence Wackett Centre for Aerospace Design Technology at RMIT University. The review investigates aspects of a proposed system for intelligent design optimisation. Such a system would be capable of efficiently storing (and compressing if required) a range of types of design data into an intelligent database. This database would be accessed by the system during subsequent design processes, allowing for search of relevant design data for re-use in later designs, allowing it to become very efficient in reducing the time for later designs as the database grows in size. Extensive research has been performed, in both theoretical aspects of the project, and practical examples of current similar systems. This research covers the areas of database systems, database queries, representation and compression of design data, geometric representation and heuristic methods for design applications.

Filling ‘gaps’ in strength data for design

Data on the physical strength capabilities of users are fundamental to the safe and usable design of products. It is recognised, however, that there are many ‘gaps’ in the ergonomics data available to designers. Whilst considerable research on human capabilities and limitations has already been carried out, few data exist which are directly applicable in the design process. This paper describes a two-stage research project which was undertaken to try to address some of these data ‘gaps’. Potential needs for design-relevant data were identified in Stage 1 of the research and in Stage 2 new data were collected to meet some of those needs. Data were collected on children through to the older adult on a series of six strength measurements, all of which were intended to be directly applicable to design: (1) finger push strength, (2) pinch-pull strength, (3) hand grip strength, (4) wrist-twisting strength, (5) opening strength, and (6) push and pull strength. The methodology, findings and data from this research are presented and discussed.

Strength Data for Designers

Data on physical strength capabilities are vital for designers to ensure that products can be used and operated safely and comfortably by all intended users. This paper describes a two stage research project which was undertaken to provide designers with such design-relevant data. Potential data needs were identified in Stage 1 of the study, and in Stage 2 new data were collected to meet those needs. The methodology, findings, and implications for universal design are presented and discussed.

Sequences and arrays derived from nonprimitive irreducible polynomials

The cycle set structure and correlation properties of the families of sequences generated by autonomous binary and multiple valued linear feedback shift registers are investigated. It is demonstrated that these sequence families arise on the rows and columns of pseudorandom arrays formed by folding certain m sequences over GF(q). Expressions are given for the weights and corre lation values for certain classes of these sequence families. Relevant design data are presented in tabular form.

An AC voltage switching regulator with instantaneous output voltage control

This is the first attempt to control the instantaneous output of an ac/ac direct power converter. The ac chopper-type regulator has the potential ability of quick response to the control command. However, detecting the mean or effective value of the ac output voltage, as is commonly done in the conventional closed-loop ac regulators, greatly degrades the inherent fast response capability of the chopper circuit. The proposed ac switching regulator adopts the Cuk converter for the main circuit and an instantaneous voltage control technique. A practical state feedback scheme together with the integral control was devised to stabilize the system and also minimize the steady-state error. The response speed is so fast (about 300 μs with resistive load) that the converter can produce a sinusoidal output voltage even from a distorted source voltage. The four-quadrant operation can handle any kind of ac load. A complete analytical description and relevant design data of this new regulator are provided with some experimental results.

Fatigue Design for Powder Metallurgy

AbstractPowder metallurgy, among several competing mass production methods, plays an important role, not only as a means of saving material and energy, but also as a technique, delivering materials with good fatigue properties which are able to substitute for conventional materials. However, it is necessary to understand the interaction between strength behaviour and design determining factors such as service loading, component geometry, and manufacturing. After presenting definitions of fatigue strength, which is divided into the areas of low cycle (endurance limit N 2 × 106) fatigue under constant amplitude loading and the area of variable amplitude fatigue with 104<N< 109, and after the introduction of parameters which describe and determine S–N or fatigue life curves, relevant design data such as S–N curves, the effect of notches and mean stresses, and fracture mechanical properties are considered. The influence of manufacturing parameters (alloy...

An AC voltage switching regulator with instantaneous output voltage control.

This is the first attempt of controlling the instantaneous output voltage of an AC/AC direct power converter. The AC chopper-type regulator has the potential ability of quick response to the control command. However, detecting the mean or effective value of the AC output voltage, as is commonly done in the conventional closed-loop AC regulators, greatly ruins the inherent fast response capability of the chopper circuit.The proposed AC switching regulator adopts the _??_uk converter for the main circuit and an instantaneous voltage control technique. A practical state feedback scheme together with the integral control was devised to stabilize the system and also minimize the steady state error. The response speed is so fast (about 300μs with resistive load) that the converter can produce a sinusoidal output voltage even from a distorted source voltage. The four quadrant operation can handle any kind of AC load. A complete analytical description and relevant design data of this new regulator are provided with some experimental results.

Fusion neutron test facility requirements for interactive effects in structural and high-heat-flux components

A relevant design data base is needed for structural components in near-term and commercial fusion devices. A high-flux, high-fluence fusion neutron test facility is required for testing the failure mechanisms and lifetime-limiting features for first wall, blanket, and high-heat-flux components. We describe here the key aspects of the fusion environment which influence the response of structural and high-heat-flux components. In addition to test capabilities for fundamental radiation-effects phenomena, e.g., swelling, creep, embrittlement, and hardening, it is shown that the facility must provide an adequate range of conditions for accelerated tests to study the limitations on component lifetime due to the interaction between such fundamental phenomena. In high-heat-flux components, testing of the failure mechanisms of duplex structures is shown to require maintenance of an appropriate temperature gradient in the 14-MeV neutron field. Thermal stresses are shown to result in component failure, particularly when the degradation in the thermal conductivity and mechanical properties by irradiation are considered. Several factors are discussed for assessment of the failure modes of the first wall and blanket structures. These are displacement-damage dose and dose rate, the amount of helium gas generated, the magnitude of irradiation and thermal creep, prototypical temperature and temperature-gradient distributions, module geometry, and external mechanical constraints.

A Computer-Aided Analysis and Design Approach for Static Voltage Source Inverters

The relative success of the ``cut and try'' method has made the design of static power converters more of an art than a science. As a result, no comprehensive analysis approach is available today that can be used to design static converters with a good degree of confidence. Some important aspects of this problem-concerning mainly static voltage source inverters-are treated in this paper within the framework of a generalized analysis and design method. The subject approach utilizes the switching function concept to derive relevant analytical expressions, and digital simulation to obtain relevant design data.