Traction modelling in train dynamics

2018 ◽  
Vol 233 (4) ◽  
pp. 382-395 ◽  
Author(s):  
Qing Wu ◽  
Maksym Spiryagin ◽  
Peter Wolfs ◽  
Colin Cole
Keyword(s):  
Three Dimensional ◽  
Traction Force ◽  
Traction Forces ◽  
Traction Control ◽  
Control Schemes ◽  
Table Model ◽  
Variable Friction ◽  
Train Dynamics ◽  
Force Reduction ◽  
Dynamics Simulations

This paper presents five locomotive traction models for the purpose of train dynamics simulations, such as longitudinal train dynamics simulations. Model 1 is a look-up table model with a constant force limit to represent the adhesion limit without modelling the wheel–rail contact. Model 2 is improved from Model 1 by empirically simulating locomotive sanding systems, variable track conditions and traction force reduction due to curving. Model 3 and Model 4 have included modelling of the wheel–rail contact and traction control. Model 3 uses a two-dimensional locomotive model while Model 4 uses a three-dimensional locomotive. Model 5 is based on Model 2 and developed to simulate hybrid locomotives. Demonstrative simulations are presented for the case of longitudinal train dynamics. The results show that the consideration of locomotive sanding systems, variable track conditions and traction force reduction have evident implications on the simulated traction forces. There can be up to 30% difference in the simulated traction forces. Simulated traction forces by models that consider the wheel–rail contact are about 10–15% lower than those simulated by models without consideration of the wheel–rail contact. This is mainly due to the variable friction in the wheel–rail contact and conservative traction control schemes.

scholarly journals Three-Dimensional Quantification of Cellular Traction Forces and Mechanosensing of Thin Substrata by Fourier Traction Force Microscopy

PLoS ONE ◽  
2013 ◽  
Vol 8 (9) ◽  
pp. e69850 ◽  
Author(s):  
Juan C. del Álamo ◽  
Ruedi Meili ◽  
Begoña Álvarez-González ◽  
Baldomero Alonso-Latorre ◽  
Effie Bastounis ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Traction Force ◽  
Traction Force Microscopy ◽  
Traction Forces ◽  
Force Microscopy

Development of Force-Feedback Technology for Training Clinicians to Deliver Manual Cervical Distraction

2013 ◽  
Author(s):  
Maruti Ram Gudavalli ◽  
Vikas Yadav ◽  
Robert Vining ◽  
Michael Seidman ◽  
Stacie Salsbury ◽  
...  
Keyword(s):  
Neck Pain ◽  
Head And Neck ◽  
Force Feedback ◽  
Controlled Trial ◽  
Three Dimensional ◽  
Traction Force ◽  
Simulated Patients ◽  
Traction Forces ◽  
Force Transducers ◽  
Graphical Feedback

Objective: Neck pain is a prevalent musculoskeletal (MSK) complaint and costly societal burden. Doctors of chiropractic (DCs) provide manual therapies for neck pain patients to relieve discomfort and improve physical function. Manual cervical distraction (MCD) is a chiropractic procedure for neck pain. During MCD, the patient lies face down on a specially designed chiropractic table. The DC gently moves the head and neck in a cephalic direction while holding a gentle broad manual contact over the posterior neck, to create traction effects. MCD traction force profiles vary between clinicians making standardization of treatment delivery challenging. This paper reports on a bioengineering technology developed to provide clinicians with auditory and graphical feedback on the magnitude of cervical traction forces applied during MCD to simulated patients during training for a randomized controlled trial (RCT). Methods: The Cox flexion-distraction chiropractic table is designed with a moveable headpiece. The table allows for long axis horizontal movement of the head and neck, while the patient’s trunk and legs rest on fixed table sections. We instrument-modified this table with three-dimensional force transducers to measure the traction forces applied by the doctor. Motion Monitor software collects data from force transducers. The software displays the magnitude of traction forces graphically as a function of time. Real-time audible feedback produces a steady tone when measured traction forces are <20N, no tone when forces range between 20–50N, and an audible tone when forces exceed 50N. Peer debriefing from simulated patients reinforces traction force data from the bioengineering technology. Results: We used audible and graphical feedback to train and certify DCs to apply traction forces to the cervical spine of simulated patients within three specific ranges. This technology supports a RCT designed to assess the ability of clinicians to deliver MCD within specified force ranges to patients randomized to different force dosages as an intervention. Future applications may include training chiropractic students and clinicians to deliver the MCD treatment.

scholarly journals A new 3D finite element-based approach for computing cell surface tractions assuming nonlinear conditions

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0249018
Author(s):  
Silvia Hervas-Raluy ◽  
Maria Jose Gomez-Benito ◽  
Carlos Borau-Zamora ◽  
Mar Cóndor ◽  
Jose Manuel Garcia-Aznar
Keyword(s):  
Inverse Problem ◽  
Finite Element ◽  
Three Dimensional ◽  
Traction Force ◽  
Nonlinear Material ◽  
Problem Solver ◽  
Microfluidic Chips ◽  
Traction Forces ◽  
Force Microscopy ◽  
Material Formulation

Advances in methods for determining the forces exerted by cells while they migrate are essential for attempting to understand important pathological processes, such as cancer or angiogenesis, among others. Precise data from three-dimensional conditions are both difficult to obtain and manipulate. For this purpose, it is critical to develop workflows in which the experiments are closely linked to the subsequent computational postprocessing. The work presented here starts from a traction force microscopy (TFM) experiment carried out on microfluidic chips, and this experiment is automatically joined to an inverse problem solver that allows us to extract the traction forces exerted by the cell from the displacements of fluorescent beads embedded in the extracellular matrix (ECM). Therefore, both the reconstruction of the cell geometry and the recovery of the ECM displacements are used to generate the inputs for the resolution of the inverse problem. The inverse problem is solved iteratively by using the finite element method under the hypothesis of finite deformations and nonlinear material formulation. Finally, after mathematical postprocessing is performed, the traction forces on the surface of the cell in the undeformed configuration are obtained. Therefore, in this work, we demonstrate the robustness of our computational-based methodology by testing it under different conditions in an extreme theoretical load problem and then by applying it to a real case based on experimental results. In summary, we have developed a new procedure that adds value to existing methodologies for solving inverse problems in 3D, mainly by allowing for large deformations and not being restricted to any particular material formulation. In addition, it automatically bridges the gap between experimental images and mechanical computations.

scholarly journals Online biophysical predictions for SARS-CoV-2 proteins

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Luciano Kagami ◽  
Joel Roca-Martínez ◽  
Jose Gavaldá-García ◽  
Pathmanaban Ramasamy ◽  
K. Anton Feenstra ◽  
...  
Keyword(s):  
Protein Sequence ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Static Structure ◽  
Homologous Proteins ◽  
Structure Based Drug Design ◽  
Protein Protein Interaction ◽  
Link Type ◽  
Dynamics Simulations ◽  
Β Sheet

Abstract Background The SARS-CoV-2 virus, the causative agent of COVID-19, consists of an assembly of proteins that determine its infectious and immunological behavior, as well as its response to therapeutics. Major structural biology efforts on these proteins have already provided essential insights into the mode of action of the virus, as well as avenues for structure-based drug design. However, not all of the SARS-CoV-2 proteins, or regions thereof, have a well-defined three-dimensional structure, and as such might exhibit ambiguous, dynamic behaviour that is not evident from static structure representations, nor from molecular dynamics simulations using these structures. Main We present a website (https://bio2byte.be/sars2/) that provides protein sequence-based predictions of the backbone and side-chain dynamics and conformational propensities of these proteins, as well as derived early folding, disorder, β-sheet aggregation, protein-protein interaction and epitope propensities. These predictions attempt to capture the inherent biophysical propensities encoded in the sequence, rather than context-dependent behaviour such as the final folded state. In addition, we provide the biophysical variation that is observed in homologous proteins, which gives an indication of the limits of their functionally relevant biophysical behaviour. Conclusion The https://bio2byte.be/sars2/ website provides a range of protein sequence-based predictions for 27 SARS-CoV-2 proteins, enabling researchers to form hypotheses about their possible functional modes of action.

scholarly journals Polymer cyclization for the emergence of hierarchical nanostructures

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chaojian Chen ◽  
Manjesh Kumar Singh ◽  
Katrin Wunderlich ◽  
Sean Harvey ◽  
Colette J. Whitfield ◽  
...  
Keyword(s):  
Self Assembly ◽  
Three Dimensional ◽  
Hierarchical Structures ◽  
Structural Similarity ◽  
Vital Role ◽  
Nanomaterial Synthesis ◽  
Wide Range ◽  
Linear Poly ◽  
Polymer Folding ◽  
Dynamics Simulations

AbstractThe creation of synthetic polymer nanoobjects with well-defined hierarchical structures is important for a wide range of applications such as nanomaterial synthesis, catalysis, and therapeutics. Inspired by the programmability and precise three-dimensional architectures of biomolecules, here we demonstrate the strategy of fabricating controlled hierarchical structures through self-assembly of folded synthetic polymers. Linear poly(2-hydroxyethyl methacrylate) of different lengths are folded into cyclic polymers and their self-assembly into hierarchical structures is elucidated by various experimental techniques and molecular dynamics simulations. Based on their structural similarity, macrocyclic brush polymers with amphiphilic block side chains are synthesized, which can self-assemble into wormlike and higher-ordered structures. Our work points out the vital role of polymer folding in macromolecular self-assembly and establishes a versatile approach for constructing biomimetic hierarchical assemblies.

Molecular Dynamics Study of Ion Impact Phenomena and Compressive Stress in Thin Films

1993 ◽  
Vol 317 ◽  
Author(s):  
N.A. Marks ◽  
P. Guan ◽  
D.R. Mckenzie ◽  
B.A. PailThorpe
Keyword(s):  
Molecular Dynamics ◽  
Three Dimensional ◽  
Carbon Films ◽  
Loss Mechanism ◽  
Ion Energy ◽  
Lennard Jones ◽  
Impact Phenomena ◽  
Ion Impact ◽  
Dynamics Simulations ◽  
The Impact

ABSTRACTMolecular dynamics simulations of nickel and carbon have been used to study the phenomena due to ion impact. The nickel and carbon interactions were described using the Lennard-Jones and Stillinger-Weber potentials respectively. The phenomena occurring after the impact of 100 e V to 1 keV ions were studied in the nickel simulations, which were both two and three-dimensional. Supersonic focussed collision sequences (or focusons) were observed, and associated with these focusons were unexpected sonic bow waves, which were a major energy loss mechanism for the focuson. A number of 2D carbon films were grown and the stress in the films as a function of incident ion energy was Measured. With increasing energy the stress changed from tensile to compressive and reached a maximum around 50 eV, in agreement with experiment.

Sign in / Sign up

Export Citation Format

Share Document