1,325 research outputs found
War and Peace in Russia\u27s Realms: A&S 100 with Karen Petrone
No full textLater this spring, Professor Karen Petrone will begin teaching a new 7-week class as part of this year\u27s Passport to the World Program: Reimagining Russia’s Realms. The class, A&S: 100 - War & Peace in Russia\u27s Realms will explore the Russian and Soviet experience of World War I, the Russian Civil War, and World War II through literature, film, and history. Additionally, students will have the opportunity to discover Russian author Leo Tolstoy’s surprisingly influential role in the development of the non-violent resistance movement.
Petrone, the chair of the Department of History, hopes to help students analyze how Russian memories of past wars shape the country today. This topic is one Petrone is already quite familiar with—so much so in fact she\u27s written a book on the subject: The Great War in Russian Memory. The course also offers a unique opportunity for students to learn about Russia\u27s past through its connection to a series of other classes and a play that students will have the opportunity to see at the end of the semester
Fatigue life prediction of lightweight electric moped frames after field load spectra collection and constant amplitude fatigue bench tests
No full textModern mobility involves increasingly electric powered assisted vehicles; the structural integrity of a lightweight
vehicle subjected to field loads for a given mission is a Fatigue Life Prediction (FLP) issue for the manufacturer:
small motorcycle companies may prefer a more sustainable experimental approach to a complex a numerical
approach.
Aim of the present work was the fatigue life prediction of the frame of an innovative electric moped for urban
commuting developed by a small manufacturer, in solo and dual riding. Given the mission adopted by the
manufacturer, a load based Fatigue Life Prediction was carried out adopting an experimental approach. The
moped frame and main components were strain gauged and statically calibrated to collect field load histories in
solo and dual riding, including extreme driving events. Constant amplitude fatigue tests were performed on the
welded tubular aluminum frame to obtain the fatigue curves at the steering tube node under horizontal loads
(N=8) and at the rear seat support node under vertical pulsated seat loads (N=8). Measured field load spectra
were extended to the design mission and used to predict the minimum required Virtual Load Life Curve (VLLC)
able to guarantee the target mission life. A damage summation value appropriate to welded aluminum structures
was adopted. The comparison of the Virtual Load Life Curve and the real component fatigue curves enabled to
evaluate the frame durability safety factors in the two considered loading conditions and to check the validity of
redesign solutions for the weakest component locations
Biaxial Testing and Analysis of Bicycle-Welded Components for the Definition of a Safety Standard
No full textThis paper presents the experimental evaluation of the fatigue behaviour of welded components under non-proportional variable amplitude biaxial loads. The study was undertaken on welded mountain bike handlebar stems, which were different in terms of geometry and technology and tested with load histories that were reconstructed and accelerated from recorded field data. Loads measured in the field were decomposed into bending and torsional components; a synchronous Peak-Valley counting, a spectrum inflation technique, a spline interpolation and a final amplification were applied to the measured signals in order to obtain test drive signals with the correct content of biaxial non-proportional loadings. After evaluation of the bending and torsion load-life curves of components under constant amplitude fatigue, the resulting data from biaxial variable amplitude fatigue tests were analysed in order to evaluate the damage contribution as a result of the two load components and an equivalent simplified two-stage constant amplitude fatigue test was proposed to the working group ISO/SC1/TC149/WG4
Analysis of the Load/Penetration Behavior of Skiing Safety A-Nets During Impact Events
No full textINTRODUCTION. In high speed skiing disciplines, safety of athletes is ultimately entrusted to A-nets when high
energy impacts have to be absorbed without contact with the obstacles behind and with minimal decelerations on
athletes. Analysis of the behavior of A-nets is a challenging study that has been addressed in the past with
experimental and numerical methods [1-3]. The knowledge of A-net tensioning and relaxation after impact is of
great importance, as well as the estimation of load/penetration curves of athletes during impacts to prevent injuries.
METHODS. Ten load cells 5 kN DMY-103 (CALT) were placed between A-nets and the zig-zag rope connected
to the steel cable tensioned between poles as in Figure 1.a, at Val Gardena Saslong race course. A 96 kg dummy,
1.1m height, was suspended with a 5.5m steel cable to the tip of the pole; lifted to the pole height, it impacted as
a pendulum against the nets at 0.4 m from the ground. Load cells measured tension loads before, during and after
each impact to get the peak loads and the load relaxation after repeated impacts (Figure 1.b). Dummy resultant
deceleration was also collected with a 500g triaxial accelerometers in the dummy, penetration was estimated by
video analysis and double integration. Static Load-Penetration curves were obtained pulling the dummy with a
load cell and a wire potentiometer, compared with the dynamic peak Load/Penetration values (Figure 1.c). Two
test sessions G1 and G2 were performed in two different locations of the slope for a total number of 30 impacts.
RESULTS. High differences between the pole location (load cells #2,3,4) and the middle portion of the net
(#5,6,7) resulted after initial tensioning (Figure 1.b). During impacts, peak values of about 1300 N were reached
on load cells close to the pole. Tension load relaxation after 8 repeated impacts reached up to 45% (Load cell #4),
with higher loss in proximity of poles. Dummy Load/Penetration non-linear curves showed that with a penetration
load of about 8 kN the dummy penetrated of about 1,5 m. Interestingly, the dummy dynamic peak penetration into
A-nets, captured with video analysis, associated to inertial load estimated by the resultant acceleration show a fair
agreement when compared to the static Load/Penetration curve (Figure 1.c).
DISCUSSION AND CONCLUSIONS. Precious information about the tensioning state of the A-nets and their
stability after repeated impacts were collected. A static Load/Penetration test can characterize the stiffness of Anet
as dynamic impact results matched with fair agreement. The test method can be proposed as an appropriate
A-net tensioning test to prevent skiers from impacting obstacles, rocks or even poles supporting the nets.
ACKNOWLWDGEMENTS. Authors intend to thank Saslong organizers and staff for the fundamental support.
REFERENCES.
[1] Petrone N. et al., Procedia Engineering, Volume 2, Issue 2, June 2010, Pages 2587-2592.
[2] Petrone N. et al., Procedia Engineering, Volume 2, Issue 2, June 2010, Pages 2593-2598.
[3] Anghileri M. et al., Journal of Crashworthiness, Vol. 19, N. 2, 2014, p. 161-171
Ski touring boots kinetic and kinematic data acquisitions for climbing and skiing analysis
No full textINTRODUCTION. Ski touring is rapidly gaining interest and increasing its pool of practisers thanks to a boost
given by the recent pandemic and the closure of ski-lifts in many regions. Differently to alpine skiing, lightness of
the gear is crucial since the practiser ascends the track without ski-lifts. Nevertheless, structural properties still
need to ensure a safe and enjoyable skiing. Ski boot is one of the key components contributing to the overall
performance of the system and its flexural stiffness in downhill has already been investigated in the past [1,2]. To
guide industry towards an optimization of the ski boot structure also in uphill climbing, a complete measurement
system was developed to collect ski boot loads and kinematics in uphill and downhill phases.
METHODS. Two six-axis load cells M3564F (Sunrise Instruments, China) were placed under front and rear
Alpinist 12 (Marker) ski touring bindings with two pairs of additional aluminium plates. Total added weight of the
load acquisition system was 0,52 kg/ski. Height added between ski and ski binding was 20 mm. To measure boot
component angles in the sagittal plane, a Tecnica Zero G ski boot was equipped with three angular potentiometric
sensors to collect the angle between: i) ski boot sole and the ski (in climbing), ii) boot shell and cuff, iii); boot
shell and skier’s tibia. Load and angle data were acquired with SoMat (HBM) data acquisition system fitted in a
compact backpack. Right side climbing and skiing data of an agonist skier (age 26 y.o., weight 70 kg) was recorded
in a mixed piste/off-piste terrain in Passo Rolle (TN, Italy) (Figure 1.a).
RESULTS. Figure 1.b reports uphill climbing total force and kinematics data of four cycles. Vertical GRF shows
a typical gait shape with two local maxima of 662 N and 686 respectively. Angular range of motion was of 60° for the ski/boot sole, 20° for the boot sole/cuff, and 17.5° for the boot sole/tibia.
DISCUSSION AND CONCLUSIONS. Results of in field test sessions will be analysed to generate data which
will be used to feed a test bench designed for applying climbing and skiing loads to ski boots.
ACKNOWLEDGEMENTS: The research was supported by the Project POR FESR 1.1.4 2020 “SAFE”.
REFERENCES.
[1] Petrone, N. et al., Sport. Eng. 2013, 16, 265–280, doi:10.1007/s12283-013-0133-z.
[2] Zhu H. et al., J Sci Med Sport. 2021 Oct;24(10):1026-1031. doi: 10.1016/j.jsams.2020.05.020.
[3] Hasler M. et al., J Sci Med Sport., 2019 Aug;22 Suppl 1:S60-S64. DOI: 10.1016/j.jsams.2018.11.009. PMID:
30527901
Comparison of the Aerodynamic Performance of Five Racing Bicycle Wheels by Means of CFD Calculations
No full textAerodynamic drag is the main source of losses in cycling so improving the bicycle aerodynamic is a fundamental key factor to increase the performance. The aim of this research is to evaluate and compare the aerodynamic performance of racing bicycle wheels by means of CFD RANS numerical models: it is based on a previous work that reported the development of the numerical model. The aim of this work is to assess the capability of CFD RANS simulations to predict the aerodynamic performance of modern racing bicycle wheels. Drag and side forces are resolved over the range of different yaw angles
Design and Application of a Portable Launching Catapult for Crash Test Simulations
No full textINTRODUCTION. In speed disciplines performed in natural ambient such as downhill skiing, racing and
downhill cycling, safety of athletes is related to the possibility of correct design of the course trajectory and
competition artifacts (i.e. jumps & walls in cycling) as well as to the correct installation of safety barriers when
dangerous elements cannot be removed from the course background (rocks, trees, drops). Not only the intrinsic
properties of structures and barriers but also their installation determine the real behaviour of such elements in the
field [1]. Crash/functional in-situ evaluation of crashworthiness or correct dynamic design of such structures gives
to course safety managers and athletes a final tool for the engineering assessment of such installations [2].
METHODS. A launching catapult for bicycle and skiing crash test simulations was designed following given
requirements of portability and energy release. The system was designed to accelerate an instrumented Hybrid III
50th male dummy and a 25 kg downhill bicycle up to an exit speed of 50 km/h in a total wooden base length of 4.0
m. In principle, two main guide beams (5.6 m) sustain a carriage (15kg) that can be accelerated by a set of 4 elastic
bands (L=1m, K=210 N/m each) each side: the bicycle/dummy assembly is guided at the floor, pulled at the
handlebars and pushed at the dummy back by the carriage. The catapult can be preloaded by a wrench and released
by a remote mechanical trigger: the carriage is stopped by two car shock absorbers. The catapult was used to test
downhill bicycle jumps with different take off angle (-4°, 0°, +4°) of the jump board and recording landing events.
RESULTS. The catapult allowed to successfully launch the dummy/bike up to 48km/h for a total number of 14
jumps. Speed can be modulated by the number of elastic bands. Dummy/bike stabilities were satisfactory and
improvement were made to prevent hand/handlebar release or dummy backflips due to the high accelerations (max
11g). Crash impacts on the downhill slope allowed recording Peak Head Resultant accelerations up to 375 g.
DISCUSSION AND CONCLUSIONS. The catapult is being adapted to other sports such as ski barriers testing
by lowering of the guide beams, introducing low friction guide for the skis, and adapting the carriage to a skiing
posture. It will be used against A-nets, B-nets and Mattresses along a racecourse after installation on the snow.
ACKNOWLEDGEMENTS. The research was funded by Interreg IV project “Goodride” ITAT 2033.
REFERENCES.
[1] Petrone N. et al., Procedia Engineering, Volume 2, Issue 2, June 2010, Pages 2593-2598.
[2] EN 1263-1,2:2014. Temporary works equipment. Safety nets safety requirements, test methods
Advances in the development of an Instrumented Human Head Surrogate for Brain Strain Experimental Evaluation during Impacts
No full textINTRODUCTION. The development of biofidelic head models is crucial since head injuries represent the most
likely outcome after a traumatic event, often leading to brain damage or death. To predict injuries and test
protective gear, several criteria were developed [1]. To improve the knowledge in this field, we developed an
Instrumented Human Head Surrogate (IHHS) [2]. New developments of this surrogate are aiming to improve the
robustness of the model with a redesigned skull, increase anatomical bio fidelity with the inclusion of falx cerebri
and tentorium cerebelli, and add more feedback with the inclusion of innovative sensors[3].
METHODS. An MRI scan of a 50th percentile male human head (scalp, skull, and brain) was imported into
Meshmixer and simplified for 3D printing. The skull model was divided in two parts joined and sealed thanks to
an indent and screws. A flat bottom base allows for connecting neck surrogates. The skull was 3D printed in PA12
using SLS technique. Brain and scalp models were used to generate moulds used for rubber casting of soft tissue
surrogates. Surrogate brain was casted using Platsil Gel 0030 silicone rubber and a Deadener in a multi-step
process embedding 3-axial accelerometers, gyros, and triads/hexads of miniature pressure sensors such as the
MAPS [3]. Skin was casted using Platsil Gel 10. Falx Cerebri and Tentorium Cerebelli were derived from the
brain model using Boolean operators and casted using Platsil gel 25. Pendulum and a drop test bench were set-up.
RESULTS. The brain with embedded sensors will be casted and assembled with skull, and skin in order to perform
impact tests with and without neck involvement. Preliminary results will be presented at the conference.
DISCUSSION AND CONCLUSIONS. We expect that these advances will improve the anatomical detail with
the inclusion of falx and tentorium and skull robustness against repeated impacts. Moreover, MAPS sensor will
allow studying dynamic multiaxial stress states in the brain during complex impact situations.
REFERENCES.
[1] Zhan X. et al., The relationship between brain injury criteria and brain strain across different types of head
impacts can be different, https://doi.org/10.1098/rsif.2021.0260, Journal of the Royal Society Interface, 6-2021.
[2] Petrone, N.et al., Feasibility of using a novel instrumented human head surrogate to measure helmet, head and
brain kinematics and intracranial pressure during multidirectional impact tests, J. Sci. Med. Sport 2019, 4–10,
doi:10.1016/j.jsams.2019.05.015.
[3] Zullo G. et al., A Novel Multi-Axial Pressure Sensor Probe for Measuring Triaxial Stress States Inside Soft
Materials, Sensors 2021, 21(10), 3487; https://doi.org/10.3390/s21103487
Gianna Petrone, La battuta a sorpresa negli oratori latini
No full textLe Bourdellès Hubert. Gianna Petrone, La battuta a sorpresa negli oratori latini. In: Bulletin de l'Association Guillaume Budé, n°1, mars 1974. pp. 130-131
Analisi comparativa del comportamento posturale e muscolare in soggetti con corsetto ortopedico
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