Anthropometric Modelling of the Pregnant Occupant

A parametric anthropometric model of a pregnant woman has been produced for use in crash protection research. The model is based on anthropometric measurements of pregnant women, with the initial model representing a 5th percentile woman in her 30th week of gestation. The model has been developed to be easily scaleable so women of different sizes can be modeled and adapted to simulate any stage of pregnancy. Previous research has simply added an enlarged abdomen to existing females models. However the model presented describes a comprehensive depiction of the altered pregnant form by incoporating the anthropometry of the entire body. This paper presents the pregnant occupant model for use in evaluation of safety systems and vehicle interiors. This work is the first step toward a computational pregnant occupant for crash protection research, capable of simulating dynamic impact response and predicting injury risk in automobile crashes.

S. I. Engine Pollution Control Using Low-Cost Palletized Catalytic Converter

I. C. Engines consume large amounts of fossil fuel emitting harmful pollutants like carbon monoxide (CO), unburnt hydrocarbons (UBHC), and oxides of nitrogen (NOx). By using a catalytic converter (CC), the carbon monoxide, hydrocarbon emissions can be transformed into less harmful carbon dioxide (CO2) & water vapor (H2O). Currently available CC’s are using costly noble metals like platinum (pt), palladium (pd), rhodium (rh) etc., hence making them expensive. This paper deals with the use of low-cost palletized silver coated alumina as the catalyst element in a CC. In this study, alumina and silver were used in the ratio of 10:1. All tests have been conducted on a stationary S.I. Engine at a constant speed of 1500 r.p.m with and without CC. Also, the performance of the palletized CC in combination with promoters like Bismuth, Cerium and Lanthanum was tested which have shown better results than silver alone as the coating element. It has been experimentally determined that the CO emissions have dropped from 7.25 (% vol) to 3.03(% vol) and the HC values have reduced from 350 ppm to 190 ppm.

Nonlinear Vibration and Comfort Analysis of High-Speed Trains Moving Over Railway Bridges

The ride comfort of high-speed trains passing over railway bridges is studied in this paper. The effects of some nonlinear parameters in a carriage-track-bridge system are investigated such as the load-stiffening characteristics of the rail-pad and the ballast, rubber elements in the primary and secondary suspensions systems. The influence of the track irregularity and train speed on two comfort indicators, namely Sperling’s comfort index and the maximum acceleration level, are also studied. Timoshenko beam theory is used for modelling the rail and bridge and two layers of parallel damped springs in conjunction with a layer of mass are used to model the rail-pads, sleepers and ballast. A randomly irregular vertical track profile is modelled, characterised by a power spectral density (PSD). The ‘roughness’ is generated for three classes of tracks. Nonlinear Hertz theory is used for modelling the wheel-rail contact.

Design for X Approach to Optimise a Formula SAE Car

The Universita` degli Studi di Firenze joined the Formula Student competition (organised by SAE and IMechE) in 2002 competing in Class 3, the following year the first car was ready to compete in Class 1. In order to build this car, an integrated approach was adopted to obtain the best solution in every aspect. The purpose of the design was to optimise the car handling, fulfilling the Formula SAE rules. All the design phases were based on the Design for X approach, with the aim to optimise all the aspects of the Formula SAE project, like performance, design and cost. A Design for Manufacturing approach was added to the FEA to design all the components, like uprights and wheel spindles, in order to simplify the CNC machining. The suspensions layout was defined using a recursive method based on the Multibody Simulation and the components design. Some experimentations were conducted to verify the simulations. The experimental data were used to start the redesign, to improve the performance of the new car that will compete in the 2004 events.

Robot Trajectory Planning Using Rational Frenet-Serret Curves

The aim of this paper is to demonstrate that the techniques of Computer Aided Geometric Design such as spatial rational curves and surfaces could be applied to Kinematics, Computer Animation and Robotics. For this purpose we represent a method which utilizes a special class of rational curves called Rational Frenet-Serret (RF) [8] curves for robot trajectory planning. RF curves distinguished by the property that the motion of their Frenet-Serret frame is rational. We describe an algorithm for interpolation of positions by a rational Frenet-Serret motion. Further more we provide an analysis on spatial frames (Frenet-Serret frame and Rotation Minimizing frame) for smooth robot arm motion and investigate their applications in sweep surface modeling.

A Mechanical Model Representation of the In Vivo Behaviour of Bulk Tissue

The aim of this study was to characterise the bulk modulus properties of the upper arm under relaxed and controlled contraction which is defined as 25% of the maximum voluntary contraction. A new testing machine was designed to generate constant load on the upper arm and measure the deformation over time. The machine consists of a device which is effectively a cuff that applies controllable pressure on a 47 mm wide band of the upper arm. Six different loads (10, 20, 30, 40, 50 and 60 kgf) were applied over a period of time of up to a maximum of 120 seconds. The deflection-time curves obtained show strongly non-linear response of the bulk tissue. The non-linearity manifested by these deflection-time curves is in terms of both time- and load-dependency. For each load, the creep behaviour follows an exponential law typical of viscoelastic materials. At low loads (below 30kgf), the creep response increases fairly linearly as the load is increased from 10 kgf to 30 kgf. But at high loads (above 30 kgf), the creep response increases only slightly as the load is increased from 30 kgf to 60 kgf. Beyond a load of 60 kgf, the deflection or creep becomes negligible. This implies that the upper arm has reached the state of incompressibility. The creep behaviour of the upper arm was simulated using four Voigt viscoelastic models in series. The three obvious soft tissues of the upper arm, namely skin, fat and muscle, were modelled in series. The effects of blood vessels and connective tissue were also modelled in series with the other tissues.

Aeroelastic Stability of a Transport Aircraft With Wing Mounted Store Suspension: Part I — Analysis

The present study outlines the analysis work, backed by the relevant ground testing, performed for the verification of aeroelastic stability of a transport aircraft modified with the installation of an external store to the outer wing. The initial analysis work consisted of free vibration analysis and ground vibration testing of the modified aircraft for the identification of the natural frequencies and associated modes of vibration in still air. The beam-like half scale model of the aircraft was updated based on the results of the ground vibration test. External store wing connection stiffness was determined by means of vibration test performed for the identification of local store-wing structural interface modes. The dynamic model was updated again and flutter analyses were performed for different mass configurations of the aircraft. Mass configurations that are critical from flutter point of view were identified. Analysis results indicate that the flutter speeds of the aircraft with wing mounted store suspension, although lowered compared to the basic aircraft, stay above the values required by the flutter regulation MIL-A-8870C.

Use of Neural Network and Discrete Wavelet Transformations in Estimation of Road Profile

This paper presents a method for estimation of road profile for automotive research applications with more accuracy and higher speed. Dynamic response of a car equipped with position and velocity sensors and driving on a sample road is used as basic data. A feed-forward neural network, trained with outputs from a car model in ADAMS, is used as the car inverse model. The neural network is capable of estimating the road roughness from the car response during test drives. The ADAMS model is corrected and validated using a series of dynamic experiments on the car, performed on a hydro-pulse test rig. The only problem in this approach, like other identification and optimization methods, is the large volume of generated data in time domain, acquired from car response during road test. This problem is solved using wavelet methods to code the acquired data. Unlike all frequency methods that eliminate a large portion of the data details during processing, the wavelet coding method restores most of the details, while the volume of the stored data is kept to a minimum. The results show that this method can estimate the road profile accurately and with great savings in processing time and effort.

Finite Element Modeling for Energy Release Rate in Human Cortical Bone

The energy release rates in human cortical bone are investigated using a hybrid method of experimental and finite element modeling techniques. An explicit finite element analysis was implemented with an energy release rate calculation for evaluating this important fracture property of bones. Comparison of the critical value of the energy release rate, Gc, shows good agreement between the finite element models and analytical solutions. The Gc was found to be approximately 820–1150 J/m2 depending upon the samples. Specimen thickness appears to have little effect on the plane strain condition and pure mode I assumption. Therefore the energy release rate can be regarded as a material constant and geometry independent and can be determined with thinner specimens. In addition, the R curve resulting from the finite element models during slow crack growth shows slight ductility of the bone specimen that indicates an ability to resist crack propagation. Oscillations were found at the onset of the crack growth due to the nodal releasing application in the models. In this study light mass-proportional damping was used to suppress the noises. Although this techniques was found to be efficient for this slow crack growth simulation, other methods to continuously release nodes during the crack growth would be recommended for rapid crack propagation.

Haemodynamics of Disturbed Flow Under Variable Shear Rate Effect

The local blood haemodynamics at curvatures and branches of the arteries system has a crucial role in controlling the localization of blood cells (i.e., leukocytes and platelets) at these sites and at sites of inflammation or vascular injuries respectively. Commonly, the local flow has different shapes of flow separation, recirculation, and non uniform shear stress distribution. To investigate these mechanisms, simulation of cell rolling and adhesion has been performed under variable position shear rate to determine the ranges of shear rates that allow for either adhesion or rolling. The results demonstrate that the cell had the three stages of cell-surface interactions (capture, adhesive rolling and secondary adhesion) when it starts at low shear rate G = 9.06 s−1. Nevertheless, at higher shear rate (i.e., 41.12 and 85.32 s−1) the cell rolls slowly for short time before its rolling velocity gradually increases to reach a maximum value as the shear rate gets higher. On the other hand, cell adhesion is dominant within the distance between the step and the stagnation point; such that the cells in this range rolsl shortly in the direction of shear rate then adheres to the surface.