The purpose of the study was to investigate clubhead kinematics during the impact phase of a golf swing. Three highly skilled golfers of a distinguished body type were instructed to perform driver, 6-iron and pitching wedge trials. A high-speed imaging system was used to capture the clubhead motion near the impact. Conventional golf swing parameters were analysed for comparison. Additionally, a circular arc was fitted to the clubhead path, and the moving trihedron was introduced as a reference frame for observing the clubhead rotation. Despite differences in their body type, golfers achieved comparable clubhead speed, while the radius of the fitted circular arc was in a narrow range. The moving trihedron, together with conventional parameters of the golf swing, enabled additional insight to the clubhead motion and clubface orientation. Individual swing characteristics, which result in the clubhead motion prior to impact, could clearly be observed, enabling improvement of the golfer’s swing technique.

Continuous improvement in the hull floor of light armoured vehicles in terms of landmine response and crew safety is required among other things, in order to meet higher demands in the market and to obtain a product safety certificate. Previous research studies have shown that V-shaped hull floors of light armoured vehicles have a better response to blast loading in terms of saving the lives of vehicle crews or reducing the number of injuries. For this reason, parametric and design optimization analyses of V-shaped hull floors play an important role in achieving an optimal, safe and cost-effective light armoured vehicle design. However, this kind of structural optimization is complex, involving a multidisciplinary fluid–structure interaction processes, as well as large structural deformations. This article presents the results of the metamodel-based parametric analysis of blast loaded armour V-plates. The contribution of most important variable parameters such as plate angle, plate thickness, explosive mass and stand-off distance to blast loading and blast response parameters was examined using a combined smooth particle hydrodynamic – finite element numerical model. The results showed that the plate angle has the greatest impact on all response parameters of the metamodel, followed by the stand-off distance and plate thickness.

Presented work is focused on experiment-based characterization and modelling of normalized and quenched and tempered low-alloy steel 42CrMo4 subjected to monotonic and cyclic loading and possibility to determine parameters of more complex models from simple ones. The main characteristics of the cyclic Ramberg-Osgood and rate-dependent as well as rate-independent Chaboche's material models, both of which are applicable for this material, have been presented. Similarities in the modelling and simulation of stabilized material behaviour confirmed possibility of such approximation for Ramberg-Osgood and rate-independent Chaboche model. However, due to inadequacy of Ramberg-Osgood for modelling of evolutionary material behaviour throughout loading cycles, separate study of the influence of saturation rate of isotropic hardening of rate-dependent Chaboche's model on modelling and simulation of material behaviour has been performed. The study showed that deviations of simulated material behaviour from the experimentally obtained behaviour are low, and in majority of the materials life negligible and recommendations on the range of values of saturation rate parameters differently heat treated 42CrMo4 steel are provided. In order to make possible further comparisons of analysed models and evaluate applicability of proposed approximations on other materials, further analyses on additional materials would need to be performed.

Engineering design process consists of three main parts: material selection, components dimensioning and the choice of production technology. The material selection relies on the knowledge of material behavior in different loading conditions. Due to their wide application, majority of research still deals with characterization of metallic materials. Innovative materials hold potential so research of characterization and modeling of their behavior is increasingly getting into focus. Therefore, it is important to resolve main objectives required for characterization of these materials. This paper discusses development of procedures required for effective soft tissues characterization, based on previously developed ones for metallic materials characterization.

In the paper, the influence of the yield-point phenomenon (YPP) on cyclic plasticity of the console beam is presented with the objective to demonstrate the impact of the YPP on the local cyclic plasticity. The influence of the YPP and its dependence on cyclic material hardening or softening was studied through experiments and numerical simulations. Console beams are made from the low-alloy EN 42 CrMo 4 steel in its normalized state (184 HV), which exhibits cyclic hardening, and in its tempered state (296 HV), which is subject to cyclic softening. Numerical simulations were performed on constitutive model of cyclic plasticity taking into account the kinematic hardening, isotropic hardening or softening and formulations of the YPP which are based on the change of the elastic region surface in the stress space at first transition into the stress plateau. Analysis of the results shows the importance of taking into account the YPP equations in constitutive models of cyclic plasticity as well as the influence of the YPP on cyclic plasticity of the console beam.

PURPOSE:Whiplash injuries to the cervical spine represent a considerable economic burden on society with medical conditions, in some cases persisting for more than a year. Numerous studies of whiplash injuries have been made for occupant normal seated position, leaving the analysis of neck injuries for out-of-normal positions not well documented. For that purpose, a detailed human cervical spine finite element model was developed.METHODS:The analysis was made for four most common occupant seated positions, such as: Normal Position with the torso against the seat back and the head looking straight ahead, Torso Lean forward position with the torso away from the seat back for approximately 10°, Head Flexed position with the head flexed forward approximately 20° from the normal position and Head-Flexed with Torso Lean forward position with the head flexed forward approximately 20° and torso 10° from the normal position.RESULTS:The comparative study included the analysis of capsular ligament deformation and the level of S-curvature of the cervical spine. The model developed predicted that Head Flexed seated position and Head-Flexed with Torso Lean forward seated position are most threatening for upper and lower cervical spine capsular ligament, respectively. As for the level of S-curvature, the model predicted that Head-Flexed with Torso Lean forward seated position would be most prone to neck injuries associated with it.CONCLUSIONS:This study demonstrated that the occupant seated position has a significant influence on potential whiplash injuries.

Many terrorist attacks in the last decade around the world have exposed the vulnerability of citizens in public places.Public trash receptacles can be easily abused as well-covered places in which Improvised Explosive Devices (IED) can be simply left and then remotely activated.Therefore, blast resistance and possibility of blast loads redirection are very important characteristics of trash receptacles placed in crowded public areas.This paper presents the results of three different trash receptacles: non-blast resistant, blast resistant and blast resistant trash receptacle with blast load redirection.The results have shown that a considerable effect can be achieved by using blast resistant receptacles, thus reducing the possibility of deaths and injuries.A thickness optimization study was additionally performed, based on the size and geometry of the opening by using a finite element model.Based on the results of the study, some valuable recommendations for design of trash receptacles are also given.

The presented system for integral management of regional public transport is based on a Geoinformation System (GIS) and includes tools for data management and display. The tools operate on a dataset that contains all the data necessary for management of public transport on rail and road. The data structure is entity-based and is methodically defined and published as a reference. All the user editable data is managed on GIS base layers (maps, orthophotographs) and publicly available GIS overlays (road, rail and waterway network, and auxiliary layers such as topography and buildings). The specific public transport data includes geographical data about station points, obtained from field measurements, user defined data about public transport itinerary segments between station points, and user editable data about public transport itineraries. Once the set of itineraries is defined, the system provides its users to create individual journeys on these. The journeys are the base for collecting the economic data, usable for the transport operators in preparing tender applications and for the managing authorities in preparing concession calls. The system incorporates all the support tools, which include a station point cataloguing form, a map editor with line section and station point management tools, itinerary creation tools with connection search abilities, and interface to GPS receivers for field work. Due to its modular structure, the system is expandable with additional data and functionality according to user needs. One such possible expansion is an interface for data collection from in-vehicle terminals. Currently, the system is targeted to regional public transport in Slovenia, but can be adapted to other regions.

An increase in the number of traffic accidents in tunnel emergency stop areas has been recored in the last two years in many countries with long road tunnels. In most cases, the collisions of passenger cars into the emergency stop area walls were fatal, which presents an even bigger obligation for the road management authorities to find a solution to the problem. Even though the tunnel emergency stop areas tunnels are designed and built according to the valid legislation, it has turned out that the current implementation of the emergency stop area wall in the driving direction presents a serious potential traffic safety risk.With the purpose of determining the most suitable method of protecting the SOS tunnel niche wall in the event of vehicle impacts, comparative numerical analysis of vehicle impacts has been performed in accordance with the SIS - EN 1317 standard. For the emergency-stop-area wall-impact protection, two different designs were considered: the H2 safety railing and the crash cushion composed of eight cylindrical steel sheet tubes. The tube diameter is 500 mm and the sheet thickness is 3 mm. Both designs were subject to collision simulations in accordance with EN 1317 parts 1 and 2 (EN 1317-1 - -4). As the safety of passenger cars was being studied, the tests TB 11 (vehicle mass 900 kg and vehicle velocity 100 km/h) and TB 21 (vehicle mass 1300 kg and vehicle velocity 80 km/h were simulated with a finite-element-model-based explicit dynamic analysis. The kinematic values of the vehicles just prior to the collision were determined by simulating the driving dynamics several seconds before the collision in PC-Crash. Based on the FEM analysis results in LS-Dyna for each crash scenario, a comparative analysis of the two protection systems was performed in order to determine their efficiency and suitability for installation in the existing tunnel emergency stop areas.Based on comparative analyses of the values of the Acceleration Severity Index (ASI), Theoretical Head Impact Velocity (THIV) and values of the Post-Impact Head Deceleration (PHD), the crash cushion provides the best results for the events of impacts of TB 11 vehicles and TB 21 vehicles into an SOS tunnel niche. (C) 2016 The Authors. Published by Elsevier B.V.

A novel multivariate and multiscale statistical process monitoring method is proposed with the aim of detecting incipient failures in large slewing bearings, where subjective influence plays a minor role. The proposed method integrates the strengths of the Independent Component Analysis (ICA) multivariate monitoring approach with the benefits of Ensemble Empirical Mode Decomposition (EEMD), which adaptively decomposes signals into different time scales and can thus cope with multiscale system dynamics. The method, which was named EEMD-based multiscale ICA (EEMD-MSICA), not only enables bearing fault detection but also offers a mechanism of multivariate signal denoising and, in combination with the Envelope Analysis (EA), a diagnostic tool. The multiscale nature of the proposed approach makes the method convenient to cope with data which emanate from bearings in complex real-world rotating machinery and frequently represent the cumulative effect of many underlying phenomena occupying different regions in the time–frequency plane. The efficiency of the proposed method was tested on simulated as well as real vibration and Acoustic Emission (AE) signals obtained through conducting an accelerated run-to-failure lifetime experiment on a purpose-built laboratory slewing bearing test stand. The ability to detect and locate the early-stage rolling–sliding contact fatigue failure of the bearing indicates that AE and vibration signals carry sufficient information on the bearing condition and that the developed EEMD-MSICA method is able to effectively extract it, thereby representing a reliable bearing fault detection and diagnosis strategy.

During the production of torsion bars, two different mechanical processes of inducing the residual stresses into the torsion bar are used: the presetting of the torsion bar and the deep rolling of the torsion bar. The process of presetting the torsion bar is carried out by twisting the torsion bar to the desired angle and releasing it to the new residual angle position. With controlled overstraining, favorable residual shear stresses are induced into the torsion bar, so the material is strain hardened and the yield point of the material is shifted and increased in the stress and strain space. The objective of the deep rolling process is to introduce compressive residual stresses into near-surface regions in order to increase the fatigue strength of the torsion bar. These two processes influence each other. The final level of residual stresses depends on the production sequence of these two processes and the production parameters of each process. The correct production sequence of these two operations and distribution of beneficial residual stress was simulated using the finite element (FE) method. To validate this model, the predicted surface residual stresses were compared by the X-ray diffraction (XRD) measurements of residual stresses.

Traditional tyre-manufacturing systems are characterised by a slow response during optimisation of the manufacturing process and insufficient adaptability to system disturbances. The objective of our research is to develop a distributed and adaptive control approach based on the concept of holonic control and IEC 61499 function blocks. A brief description of the manufacturing modules within the "green"-tyre manufacturing system is given. The architecture of distributed holonic control and implementation environment using IEC 61499 function blocks are then proposed and elaborated. Comprehensive discussion is given thereafter, including an evaluation of the distributed holonic control approach within the virtual manufacturing environment based on simulation tests for various scenarios, whereby system operation in unstable conditions is taken into account. The real-life implementation of this technology in the future is expected to increase productivity, resource utilisation and robustness in a tyre-manufacturing environment. (C) 2016 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.

The article presents the influence of the yield-point phenomenon (YPP) on the cyclic plasticity of the uniaxial cyclically-loaded specimens based on observation of stress–strain responses and imaging of strain fields. The phenomenon and its dependence on cyclic material hardening or softening was studied through experiments conducted on the low-alloy EN 42CrMo4 steel in its normalised state (184HV), which exhibits cyclic hardening, and in its tempered state (296HV), which is subject to cyclic softening. The results of the study express the influence of the YPP on cyclic plasticity through inhomogeneous strain field when specimens are loaded with strain amplitudes within the yield plateau. The YPP is well expressed in uniaxial cyclic experiments of cyclically softening material.

This work is focused on a parametric numerical study of the barrier’s bar inclination shelter effect in crosswind scenario. The parametric study combines mesh morphing and design of experiments in automated manner. Radial Basis Functions (RBF) method is used for mesh morphing and Ansys Workbench is used as an automation platform. Wind barrier consists of five bars where each bar angle is parameterized. Design points are defined using the design of experiments (DOE) technique to accurately represent the entire design space. Three-dimensional RANS numerical simulation was utilized with commercial software Ansys Fluent 14.5. In addition to the numerical study, experimental measurement of the aerodynamic forces acting on a vehicle is performed in order to define the critical wind disturbance scenario. The wind barrier optimization method combines morphing, an advanced CFD solver, high performance computing, and process automaters. The goal is to present a parametric aerodynamic simulation methodology for the wind barrier shelter that integrates accuracy and an extended design space in an automated manner. In addition, goal driven optimization is conducted for the most influential parameters for the wind barrier shelter.

In this article, the process of deep rolling of the torsion bar for heavy armored vehicles is investigated. Deep rolling is a mechanical process of introducing compressive stresses into near surface regions of the working piece. The main objective of deep rolling of the torsion bar is to increase fatigue strength and life time of the torsion bar. The investigated specimen (quenched and tempered before deep rolling) was deep rolled according to the producer's standard technology procedure. The material used in this study was the TORKA steel, which is a low-alloy steel with high strength and toughness. The material was characterized through a series of monotonic and cyclic tension compression experiments. Parameters used in the process were changed during deep rolling of the specimen and their influence was measured. Residual stresses resulting from the deep rolling process were measured with an X-ray diffraction (XRD) device and evaluated with the use of commercial finite element method software. An isotropic and kinematic hardening material model based on the cyclic characteristics of the material was used in three dimensional simulation of deep rolling. Numerical simulation results agree very well with the results obtained from XRD measurements.

This paper discusses the flow and fracture properties of high-strength armor steel PROTAC 500. Based on combination of both experimental and numerical studies, material parameters for the Johnson-Cook (JC) strength and fracture model were determined. For that purpose, experimental tensile tests were conducted at elevated temperatures (20-400 degrees C), various strain rates (0.001-1 s(-1)) and triaxialities of axisymmetric notched specimens (0.333-1.431). Some test specimens were photographed during the testing, and by means of image processing, input data for calculation of true stresses and strains up to the point of fracture were extracted. After determination of strength material parameters, tensile axisymmetric tests with different triaxialities were numerically simulated and triaxiality data from the simulations were taken for evaluation of the material parameters of the damage model. Validation study was also performed successfully. The results of this paper will enable numerical prediction of large deformation processes as well as possible fracture occurrence, its development and final size, for structures made of high strength armor steel, PROTAC 500. (C) 2014 Elsevier Ltd. All rights reserved.

Due to the increasing number of traffic accidents involving the collisions of vehicles with the emergency-stop-area head walls in tunnels, a comparative numerical analysis in accordance with the EN 1317 standard has been performed in order to assess the quality of the available protective safety barriers. Based on the simulation results, the values of the relevant injury criteria - the acceleration severity index (ASI), the theoretical head impact velocity (THIV) and the post-impact head deceleration (PHD) - were computed for several collision scenarios involving two different passenger vehicles colliding with two different safety barriers in various ways. The results show that due to the geometrical restrictions in the tunnel's emergency stop area none of the barriers can provide total protection for the occupants of the vehicle in the event of a collision. The installation of a steel-sheet-tube crash cushion was, however, found to provide the best possible protection within the given limitations. The results of the analysis were the basis for selecting a safety-barrier design for existing tunnel installations and for the proposed changes in regulations governing the geometry of the tunnel's emergency stop area.

Mechanical properties of cervical spine ligaments are of great importance for an accurate finite element model when analyzing the injury mechanism. However, there is still little experimental data in literature regarding fresh human cervical spine ligaments under physiological conditions. The focus of the present study is placed on three cervical spine ligaments that stabilize the spine and protect the spinal cord: the anterior longitudinal ligament, the posterior longitudinal ligament and the ligamentum flavum. The ligaments were tested within 24-48 hours after death, under two different loading rates. An increase trend in failure load, failure stress, stiffness and modulus was observed, but proved not to be significant for all ligament types. The loading rate had the highest impact on failure forces for all three ligaments (a 39.1% average increase was found). The observed increase trend, compared to the existing increase trends reported in literature, indicates the importance of carefully applying the existing experimental data, especially when creating scaling factors. A better understanding of the loading rate effect on ligaments properties would enable better case-specific human modelling.