Moving Contact Problem of an Unbonded Layer in the Presence of Body Force

2021 ◽  
Author(s):  
İsa Çömez
Keyword(s):  
Contact Problem ◽  
Body Force ◽  
Moving Contact

Modeling of Facet Articulation as a Nonlinear Moving Contact Problem: Sensitivity Study on Lumbar Facet Response

1998 ◽  
Vol 120 (1) ◽  
pp. 118-125 ◽  
Author(s):  
M. Sharma ◽  
N. A. Langrana ◽  
J. Rodriguez
Keyword(s):  
Contact Problem ◽  
Spatial Orientation ◽  
Facet Joint ◽  
Sensitivity Study ◽  
Geometric Parameters ◽  
Load Transmission ◽  
Moving Contact ◽  
Articular Surfaces ◽  
Motion Segment ◽  
Flexion Extension

A finite element (FE) based scheme for modeling facet articulation in a spinal motion segment is proposed. The algorithm presented models the facet articulation as a nonlinear progressive contact problem. This algorithm is used to perform a nonlinear FE analysis of a complete L3-L4 motion segment. The role of facets in load transmission through a motion segment and its sensitivity to facet geometric parameters (i.e., spatial orientation of the facets and the gap between the facet articular surfaces) on this load transmission are studied. Compression, flexion, extension, and torsion loads are used in this study. The effect of facetectomy on gross segment response and disk fiber strains is studied by comparing the response of FE models of motion segment with and without facets. Large facet loads are obtained when the motion segment is subjected to torsional and large extension rotations, whereas minimal facet loads are observed under compression and flexion loading. Removal of facets reduces the segment stiffness considerably in torsion and results in higher strain levels in disk fibers. The facet load transmission is sensitive to facet geometric parameters, i.e., spatial orientation and initial facet joint gap. The facet loads increase uniformly with decrease in initial gap between the facet articular surfaces under compression, extension, and torsional loads. The sensitivity to spatial orientation angles of the facet is, however, found to vary with the type of loading. This sensitivity may account for the wide variation in the facet response reported in literature.

On the contact problem of a moving rigid cylindrical punch sliding over an orthotropic layer bonded to an isotropic half plane

2020 ◽  
Vol 25 (10) ◽  
pp. 1924-1942
Author(s):  
I Çömez ◽  
MA Güler
Keyword(s):  
Integral Equation ◽  
Singular Integral Equation ◽  
Contact Problem ◽  
Half Plane ◽  
Singular Integral ◽  
Integral Transform ◽  
Orthotropic Layer ◽  
Moving Contact ◽  
Contact Width ◽  
Cylindrical Punch

In this study, the frictional moving contact problem for an orthotropic layer bonded to an isotropic half plane under the action of a sliding rigid cylindrical punch is considered. Boundary conditions of the problem include the normal and tangential forces applied to the layer with a cylindrical punch moving on the surface of the layer in the lateral direction at a constant velocity V. It is assumed that the contact area is subjected to the sliding condition where Coulomb’⣙s law is used to relate the tangential traction to the normal traction. Using the Fourier integral transform technique and Galilean transformation, the plane contact problem is reduced to a singular integral equation in which the unknowns are the contact stress and the contact width. The singular integral equation is solved numerically using Gauss–Jacobi integration formulae. Numerical results for the contact widths and the contact stresses are given as a solution.

Simulation of Body Force Impact on the Assembly Process of Aircraft Parts

2019 ◽  
Author(s):  
Sergey Lupuleac ◽  
Aleksandr Smirnov ◽  
Maria Churilova ◽  
Julia Shinder ◽  
Nadezhda Zaitseva ◽  
...  
Keyword(s):  
Quadratic Programming ◽  
Contact Problem ◽  
Body Force ◽  
Numerical Approach ◽  
Manufacturing Technology ◽  
Assembly Process ◽  
Integration Process ◽  
Force Vector ◽  
Force Impact ◽  
Correction Terms

Abstract The manufacturing technology of some aircraft parts involves rotation of parts in assembly jig during the integration process. As the jig rotates, the gravity acting on the parts changes its direction. It can affect the residual gap between parts joined with temporary fasteners and lead to eccentricity of drilled holes for rivets. A numerical approach for simulation of airframe assembly process with account of this effect is discussed in the paper. The approach is based on reformulation of contact problem in terms of quadratic programming and introduction of special correction terms in the force vector. The developed approach is applied to evaluation of effect of assembly rotation on the contact quality.

Moving contact line

2001 ◽  
Vol 11 (PR6) ◽  
pp. Pr6-199-Pr6-212 ◽  
Author(s):  
Y. Pomeau
Keyword(s):  
Contact Line ◽  
Moving Contact Line ◽  
Moving Contact
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