A polygonal-FEM technique in modeling large sliding contact on non-conformal meshes

2015 ◽  
Vol 32 (5) ◽  
pp. 1391-1431 ◽  
Author(s):  
Amir R. Khoei ◽  
R. Yasbolaghi ◽  
S.O.R. Biabanaki
Keyword(s):  
Contact Surface ◽  
Contact Problems ◽  
Sliding Contact ◽  
New Technique ◽  
Shape Functions ◽  
Content Type ◽  
Non Linear ◽  
Polygonal Elements ◽  
A New Technique ◽  
Interpolation Functions

Purpose – In this paper, the polygonal-FEM technique is presented in modeling large deformation – large sliding contact on non-conformal meshes. The purpose of this paper is to present a new technique in modeling arbitrary interfaces and discontinuities for non-linear contact problems by capturing discontinuous deformations in elements cut by the contact surface in uniform non-conformal meshes. Design/methodology/approach – The geometry of contact surface is used to produce various polygonal elements at the intersection of the interface with the regular FE mesh, in which the extra degrees-of-freedom are defined along the interface. The contact constraints are imposed between polygonal elements produced along the contact surface through the node-to-surface contact algorithm. Findings – Numerical convergence analysis is carried out to study the convergence rate for various polygonal interpolation functions, including the Wachspress interpolation functions, the metric shape functions, the natural neighbor-based shape functions, and the mean value shape functions. Finally, numerical examples are solved to demonstrate the efficiency of proposed technique in modeling contact problems in large deformations. Originality/value – A new technique is presented based on the polygonal-FEM technique in modeling arbitrary interfaces and discontinuities for non-linear contact problems by capturing discontinuous deformations in elements cut by the contact surface in uniform non-conformal meshes.

En bloc petrosectomy using a Gigli saw for petroclival lesions

1995 ◽  
Vol 83 (3) ◽  
pp. 559-560 ◽  
Author(s):  
Tomio Sasaki ◽  
Makoto Taniguchi ◽  
Ichiro Suzuki ◽  
Takaaki Kirino
Keyword(s):  
Facial Nerve ◽  
Semicircular Canals ◽  
Petrous Bone ◽  
New Technique ◽  
En Bloc ◽  
Content Type ◽  
A New Technique ◽  
Transtentorial Approach ◽  
Fine Print

✓ The authors report a new technique for en bloc petrosectomy using a Gigli saw as an alternative to drilling the petrous bone in the combined supra- and infratentorial approach or the transpetrosal—transtentorial approach. It is simple and easy and avoids postoperative cosmetic deformity. This technique has been performed in 11 petroclival lesions without injuring the semicircular canals, the cochlea, or the facial nerve.

A new technique for exposure of the cervical spine laminae

2002 ◽  
Vol 96 (1) ◽  
pp. 122-126 ◽  
Author(s):  
Tateru Shiraishi
Keyword(s):  
Cervical Spine ◽  
New Technique ◽  
Diverse Range ◽  
Content Type ◽  
Spinous Processes ◽  
Technical Details ◽  
A New Technique ◽  
Fine Print

✓ The author describes a new technique for exposure of the cervical spine laminae in which the attachments of the semispinalis cervicis and multifidus muscles to the spinous processes are left untouched. It provides a conservative exposure through which a diverse range of posterior cervical surgeries can be performed. In contrast to conventional cervical approaches, none of the muscular attachments to the spinous processes is compromised. In this paper the author describes the technical details and discusses the applications of the procedure.

A virtual element method for frictional contact including large deformations

2019 ◽  
Vol 36 (7) ◽  
pp. 2133-2161 ◽  
Author(s):  
Peter Wriggers ◽  
Wilhelm T. Rust
Keyword(s):  
Large Deformation ◽  
Contact Problems ◽  
Stable Node ◽  
Virtual Element Method ◽  
Polygonal Mesh ◽  
Content Type ◽  
Polygonal Elements ◽  
Virtual Element ◽  
Adaptively Adjusting ◽  
Element Method

Purpose This paper aims to describe the application of the virtual element method (VEM) to contact problems between elastic bodies. Design/methodology/approach Polygonal elements with arbitrary shape allow a stable node-to-node contact enforcement. By adaptively adjusting the polygonal mesh, this methodology is extended to problems undergoing large frictional sliding. Findings The virtual element is well suited for large deformation contact problems. The issue of element stability for this specific application is discussed, and the capability of the method is demonstrated by means of numerical examples. Originality/value This work is completely new as this is the first time, as per the authors’ knowledge, the VEM is applied to large deformation contact.

A three-dimensional fusion prediction model for fractal rough surfaces in the sliding contact process

2014 ◽  
Vol 66 (3) ◽  
pp. 459-467
Author(s):  
Yan Lu ◽  
Zuomin Liu
Keyword(s):  
Temperature Rise ◽  
Rough Surfaces ◽  
Normal Load ◽  
Contact Process ◽  
Three Dimensional ◽  
Contact Problems ◽  
Sliding Contact ◽  
Content Type ◽  
Solution Methods ◽  
Account Temperature

Purpose – The purpose of this manuscript is to analyze the fusion micro-zone generated by typical rough surfaces and investigate the factors of thermal effects on the tribological performance of surface asperities and its results verified by the experiment. Design/methodology/approach – A three-dimensional fractal rough surfaces sliding contact model has been developed, which takes into account temperature rise and distribution. The finite-element method, Green's function method, thermal conduct theory and contact mechanics are used as the solution methods. Findings – The results yield insights into the effects of the sliding velocity, thermal properties of the material, normal load and surface roughness on the temperature rise of the sliding contact surface. It allows the specification of working conductions' properties to reduce fusion. Originality/value – The model is developed and described by using the features of the contact between one flat surface and one rough surface with varied topographies. It can be easily applied for solving the sliding contact problems with different working conditions and specified for designing the surface accuracy in the severe working condition.

A subarachnoid screw for monitoring intracranial pressure

1973 ◽  
Vol 39 (3) ◽  
pp. 416-419 ◽  
Author(s):  
John K. Vries ◽  
Donald P. Becker ◽  
Harold F. Young
Keyword(s):  
Intracranial Pressure ◽  
Local Anesthesia ◽  
Subarachnoid Space ◽  
New Technique ◽  
Content Type ◽  
A New Technique ◽  
Fine Print

✓ A new technique for monitoring intracranial pressure is presented. It is based on a hollow screw in the skull whose tip projects through the dura into the subarachnoid space. The screw can be easily inserted under local anesthesia. Pressure is monitored isovolumetrically by connecting the screw to a transducer. The system can be calibrated in situ and has been successfully used in 56 patients during a 6-month period.

Selective posterior rhizotomy for treatment of spasticity

1983 ◽  
Vol 58 (6) ◽  
pp. 895-899 ◽  
Author(s):  
Lauri V. Laitinen ◽  
Stefan Nilsson ◽  
Axel R. Fugl-Meyer
Keyword(s):  
General Anesthesia ◽  
Muscle Contractions ◽  
New Technique ◽  
Similar Technique ◽  
Good Reduction ◽  
Content Type ◽  
Tonic Muscle ◽  
A New Technique ◽  
Selective Posterior Rhizotomy ◽  
Fine Print

✓ In 1976, Fasano, et al., described a new technique of posterior rhizotomy for treatment of spasticity. They stimulated electrically fascicles of the posterior roots in spastic patients and found that some fascicles responded to stimulation with tonic muscle contractions. They cut these fascicles, preserving those with a weaker or no reaction. The present authors have used a fairly similar technique in the treatment of eight patients with spasticity of the legs and one patient with spasticity of the arm: all fascicles of the posterior roots T12-S1 and C6–8, respectively, were stimulated electrically during surgery under general anesthesia. Approximately 60% to 80% of the fascicles responded to stimulation with tonic muscle jerks, and only these fascicles were cut. All nine patients showed a good reduction of spasticity. The residual cutaneous and joint sensation remained unchanged. Motility of the limbs usually improved.

scholarly journals Non-linear sweep voltammetry of adsorbed species: theory and a method to determine formal potentials

2017 ◽  
Vol 19 (42) ◽  
pp. 28820-28823 ◽  
Author(s):  
Enno Kätelhön ◽  
Richard G. Compton
Keyword(s):  
Linear Sweep Voltammetry ◽  
New Technique ◽  
Linear Sweep ◽  
Adsorbed Species ◽  
Non Linear ◽  
A New Technique

The equilibrium voltammetry of surface-bound analytes is investigated and a new technique to measure formal potentials introduced.

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