66,736 research outputs found
Parallel session 1 : Teaching and learning innovations
No full textPresented Titles: Promoting Self-compassion and Self-reflection Through the Use of Action Method as Interactive Agent in Counsellor Training [Authors: Yee-lap To; Pui-chi Tse; Wai Fu] Meaning Creation: Writing in English but Thinking in First Language [Author: Namal Wickramasekera] Negative Emotions Induced by Feedback and Emotion Regulation of Hong Kong University Students: Exploring the Role of Feedback Orientation [Authors: Lan Yang; Yiqi Wu
Lap time simulation for racing car design
No full textRacing teams use numerous computational tools (CAD, FEA, CFD) to aid in the design of racing cars and the development of their performance. Computer
simulation of racing car handling through Lap Time Simulation (LTS) packages complements these tools. It also allows teams to examine the effect of different vehicle parameter setups to optimise vehicle performance. In similarity with the automotive industry, time is limited and rapid development of new ideas and technology is essential. Thus, the use of a more sophisticated computer simulation would allow a team to gain a significant advantage over their competitors.
As LTS are computationally intensive,previous packages
have simulateda full lap using a quasi-static method which splits the path of the vehicle into segments. An
analysis is then made of the vehicle at each segment point using the external forces acting on the vehicle. Due to the constant acceleration(i.e. steady state) assumption
across each segment, this method does not take into account the effect of roll, pitch and yaw inertia as well as damping and tyre lag effects. Another aspect that is not
accounted for is the variation in the fastest effective vehicle path along the circuit (i.e.racing line) due to change in driver control inputs or vehicle parameters.
The overall aim of this thesis is to develop a transient LTS methodology, which adopts a strategy to vary the racing line taken in order to address the problems found with the existing quasi-static LTS packages. In parallel an investigation of the accuracy of vehicle models in relationship to racing car performance has been
developed.
The thesis begins with a study of racing car modelling techniques and a review of current LTS packages. A description is then given of the collection of vehicle handlingd ataf rom an actualr acingc ar (alongw ith attaining a vehicle parametesr et) and the measured
results displayed and discussed.
The creation of two vehicle models, a simple and sophisticated version, is detailed and the measured results are compared to the simulated results of each vehicle
model. It was found that the simple vehicle model does not fully represent the actual vehicle's lateral dynamic behaviour, although its steady state response was deemed
to be accurate. The sophisticated vehicle model was seen to not only accurately predict the full range of lateral dynamic behaviour of the actual vehicle, but also the
actual vehicle's longitudinal and combined lateral and longitudinal dynamic behaviour.
To further investigate LTS techniques, a comparison study was made between various simulation approaches which indicated that the transient approach, although
more complicated and time consuming, allows for more accurate tuning of a greater number of vehicle parameters.
Finally, the creation of two simulation packages has been detailed and case studies are presented to provide further insight into the look and feel of the packages. The
first package is a quasi-static approach based LTS package, where a case study is made into the sensitivity of overall lap time to a range of vehicle parameters. The second is a transient approach based simulation package which optimises the driver controls,varying the racing line taken by the vehicle and ensuring the manoeuvre is completed in the quickest time for that vehicle parameter set. This final Manoeuvre Time Minimisation package fulfils the overall aim of the thesis and a case study is made into the effect of front damping value on manoeuvre completion time
Lap splices of bars in bundles
No full textEuropean (EC2) and ACI 318-08 design code rules for lap splicesof reinforcing bars within a bundle differ markedly—the formerpermits the same or shorter lap-splice lengths with respect tosplices of individual bars, while the latter requires longer laps. Thispaper reports an investigation into the performance of lap splicesof individual bars within a bundle of two or three. The results showthat the bond strength of individual bars is not reduced on accountof their forming part of a bundle (contrary to the provisions ofACI 318-08). Staggered laps were found to be weaker but fail ina less brittle manner when splices are staggered longitudinally ascompared to equivalent laps, where all bars are spliced at the samesection whether or not bars were bundled. Therefore, the outcomeraises the question of the validity of reductions permitted by boththe ACI 318-08 and European (EC2) codes, where only a portion ofthe bars is lap-spliced at a section. It is recommended that furtherinvestigation of the influence of the proportion of bars lapped at asection on splice performance be undertaken
A finite element modelling methodology for the non-linear stiffness evaluation of adhesively bonded single lap-joints. Part 1, Evaluation of key parameters
No full textReported in this paper is the development and verification of a finite element model with the fewest solid elements that can predict the non-linear stiffness characteristics of adhesively bonded single lap-joints in vehicle bodies. This work was driven by the need to significantly reduce computing hardware resources and run times for whole body analyses, and to achieve this goal the lap-joint needs to be modelled by a ‘small’ number of shell elements. It is well-known that the deformation of bonded lap-joints is dependent on seven key parameters, and that it is impractical to have a comprehensive characterisation of these by physical testing alone. To gain further understanding of the influence of these parameters on joint stiffness, over a wider range of variables than could be practically achieved in the laboratory, the ANSYS finite element code is used to simulate the highly non-linear (geometric and material) response of bonded joints. The authors use the laboratory results for joint stiffness from nineteen batches of laboratory specimens to aid the development, and verification, of numerical derived stiffness curves from a solid element model. Initially, a very refined mesh is used. This model is developed to have a ‘coarse’ solid element mesh that minimises run times without the calculated joint stiffness deviating by more than 10% from the batch mean of 10 measurements from laboratory testing. Numerical results from many simulations using the ‘coarse’ solid mesh model are used to show that, for the shell modelling methodology (reported in Part 2 on this work) to be successful, a representative model must account for the four key parameters of: adherend stress–strain relationship, adherend thickness, bond line thickness, and the over lap length. The ANSYS results also confirm that stiffness is directly proportional to joint width
Hybrid (bolted/bonded) joints applied to aeronautic parts : analytical one-dimensional models of a single-lap joint
No full textThe load transfer in hybrid (bolted/bonded) single-lap joint is complex due to the association of two different transfer modes (discrete and continuous) through elements with different stiffness. Analytical methods exist for these two different modes, when considered separately. In this paper two one-dimensional elastic analytical models are presented for the determination of the load transfer in single lap configuration. The first one is developed by using the integration of the local equilibrium equations. From this first method an elastic-plastic approach is presented. The second one uses the Finite Element Method, introducing a new element called “bonded-bar”. These models are robust, easy to use and provide the same results. They allow to analyze the load transfer and to evaluate different geometric and mechanical parameters’ influence. Thus they represent the first step for the design of a hybrid joint able to replace its bolted equivalent used on aircraft
Respectability, morality and disgust in the night-time economy: exploring reactions to ‘lap dance’clubs in England and Wales
No full textThe night-time economy is often described as repelling consumers fearful of the ‘undesirable Others’ imagined dominant within such time-spaces. In this paper we explore this by describing attitudes towards, and reactions to, one particularly con- tentious site: the ‘lap dance’ club. Often targeted by campaigners in England and Wales as a source of criminality and anti-sociality, in this paper we shift the focus from fear to disgust, and argue that Sexual Entertainment Venues (SEVs) are opposed on the basis of moral judgments that reflect distinctions of both class and gender. Drawing on documentary analysis, survey results and interview data collected during guided walks, we detail the concerns voiced by those anxious about the presence of lap dance or striptease clubs in their town or city, particularly the notion that they ‘lower the tone’ of particular streets or neighbourhoods. Our conclusion is that the opposition expressed to lap dance clubs is part of an attempt to police the bound- aries of respectable masculinities and femininities, marginalizing the producers and consumers of sexual entertainment through ‘speech acts’ which identify such enter- tainment as unruly, vulgar and uncivilized. These findings are considered in the light of ongoing debates concerning the relations of morality, respectability and disgust
Lapped joints in reinforced concrete
No full textThis thesis is concerned with an experimental investigation of the behaviour of lapped joints in reinforced concrete. A review of existing literature highlights the need to establish the longitudinal strain distribution along lap joints. This has been achieved experimentally, with detailed strain measurements being taken using a technique of internally gauging the reinforcing rods. In some specimens, strain concentration gauges were installed at the tip of the lap to permit the acquisition of particularly localised information. Computer programs were developed to process the substantial amounts of data generated during the course of each test. Two series of tests were undertaken, both using axially loaded specimens, and dealing with tension and compression lap joints respectively. The laps ranged in length from 125 to 750 mm, and comprised bars of either 12 or 20 mm diameter. Transverse reinforcement was provided in two of the tension specimens. Greater emphasis was placed on the first series, with fifteen tension specimens being tested. Thirteen of these tests were each completed within a single day but, additionally, two long-term tests were undertaken. In the latter, a constant load was sustained for up to 81 days. The measurements clearly showed the changing behaviour of the specimens, first as transverse cracks developed and subsequently as failure of the lap joint was approached. The comprehensive analysis of the test results includes a comparison of the ultimate behaviour of these joints with existing design proposals and regulations. The detailed information provided by the strain measurements enables the justification of design assumptions regarding lap joint behaviour, and thus lends greater confidence to existing design regulations. The results from five compression specimens were analysed and compared with the tension tests. The significant contribution to force transfer made by the bearing of the free end of the steel against the concrete was evident. The specimens were loaded to the rig capacity without failing. Additional strain measurements were taken in one tension and one compression specimen by casting embedment gauges within the concrete. These gauges were arranged to measure the circumferential strains in the specimen, and were complemented by strain gauges mounted on the surface of the concrete. The data thus obtained permitted a comparison of the bursting forces set up inside and outside the lap joints. The work showed that some aspects of lap joint behaviour require clarification. Suggestions for further work are included
Kai-Yee Woo interview
No full textKai-Yee Woo remembers learning a key principal of design from the Dean of Environmental Design. She talks about campus life during her time at CCAC. She recalls how her final presentation led to her first job
Lap time simulation with transient vehicle and tyre dynamics
No full textA numerical method is presented for the time optimal control of the race car. The method
is then used to perform the role of the driver in numerical simulations of manoeuvres at the
limit of race car performance. The method does not attempt to model the driver but rather
replaces the driver with methods normally associated with numerical optimal control. The
use of constraints on the method is then considered to represent the performance limits of
the human driver. The method simultaneously finds the optimal driven line and the driver
control inputs (steer, throttle and brake) to drive this line in minimum time. The method is
in principle capable of operation with arbitrarily complex vehicle models as it requires only
limited access to the vehicle model state vector. It also requires solution of the differential
equation representing the vehicle model in only the forward time direction and is hence
capable of simulating the full vehicle transient response. The impact of various vehicle
parameters on minimum manoeuvre time, driven line and vehicle stability is shown for a
number of representative manoeuvres using a quasi-steady state vehicle model. A similar
process is then carried out to analyse the effect of suspension springs and dampers using a
fully dynamic sprung vehicle model. The presented transient time optimal control method
is then compared with results obtained from a traditional quasi-steady state manoeuvre
time simulation method. A thermodynamic tyre model is developed and the time optimal
control algorithm is used to evaluate dynamic tyre temperature effects on lap time and
vehicle stability
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