Contact mechanical problem for arbitrary 3D loading histories

Weld build-up or weld cladding is a welding process in which weld metal can be deposited in order to reclaim the material thickness. In certain applications, welding induced distortions must be controlled while simultaneously minimizing welding induced residual strains. In order to examine the relative effect of the weld build-up region on welding induced distortion and residual strains, two panels were fabricated with either a small 100 × 100 × 3 or large 200 × 200 × 3 mm depression that was subsequently filled by welding. During welding, the strains, displacements and temperature were continuously monitored in order to compare the transient solution with companion FEM models of the same structures. The coupled thermo-mechanical problem was solved using Goldak Technology Inc.s VrSuite program, with the level of agreement of the measured distortions, strains and temperature profiles dependent on their location and history. Both the numerical and experimental tests showed that despite the differences in the geometry, both panels developed the same strain state, although the large welded patch had greater peak value and larger distortions.

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Architectural changes of trabecular bone caused by the remodeling process

MRS Proceedings ◽

10.1557/proc-874-l1.9 ◽

2005 ◽

Vol 874 ◽

Author(s):

Richard Weinkamer ◽

Markus A. Hartmann ◽

Yves Brechet ◽

Peter Fratzl

Keyword(s):

Trabecular Bone ◽

Feedback Loop ◽

Mechanical Response ◽

Volume Fraction ◽

Bone Volume ◽

Bone Architecture ◽

Mechanical Problem ◽

Bone Volume Fraction ◽

Obvious Effect ◽

Trabecular Bone Architecture

AbstractUsing a stochastic lattice model we have studied the architectural changes of trabecular bone occurring while the structure is remodeled. Our model considers the mechanical feedback loop, which control the remodeling process. A fast algorithm was employed to solve approximately the mechanical problem. A general feature of the model is that a networklike structure emerges, which further coarsens while the bone volume fraction remains unchanged. Decreasing the mechanical response of the system by either lowering the external load or the internal mechano-sensitivity leads not only to a reduction of the bone volume fraction, but results in topological changes of the trabecular bone architecture, where the loss of horizontal trabeculae is the most obvious effect.

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Mechanical problem in 3D printed ankle-foot orthoses with function of energy storage

10.1063/1.5081539 ◽

2018 ◽

Cited By ~ 1

Author(s):

Chien-Hsien Yeh ◽

Yi-Chun Tsai ◽

Fong-Chin Su ◽

Li-Chieh Kuo ◽

Kai Chang ◽

...

Keyword(s):

Energy Storage ◽

Foot Orthoses ◽

Mechanical Problem ◽

Ankle Foot Orthoses ◽

3D Printed

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Visualization of Multiaxial Stress/Strain State and Evaluation of Failure Life by Developed Analyzing Program under Non-Proportional Loading

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.891-892.1391 ◽

2014 ◽

Vol 891-892 ◽

pp. 1391-1396

Author(s):

Shu Li Liu ◽

Takamoto Itoh ◽

Noriyuki Fujii

Keyword(s):

Principal Stress ◽

Strain State ◽

Strain Range ◽

Mean Stress ◽

Damage Evaluation ◽

Multiaxial Loading ◽

Proportional Loading ◽

Stress Strain ◽

3D Loading ◽

Failure Life

This study presents definitions of principal stress/strain range and mean stress/strain introduced by utilizing Itoh-Sakane criterion for multiaxial loading including non-proportional loading, and shows the method of calculating the non-proportional factor which expresses the severity of non-proportional loading under the multiaxial 3D loading. This paper also shows a method of visually presenting the stress/strain, the non-proportionality of loading and the damage evaluation.

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Analysis of Contact Mechanical Characteristics of Flexible Parts in Harmonic Gear Reducer

Shock and Vibration ◽

10.1155/2021/5521320 ◽

2021 ◽

Vol 2021 ◽

pp. 1-17

Author(s):

Fanjie Li ◽

Xiaopeng Li ◽

Yajing Guo ◽

Dongyang Shang

Keyword(s):

Mechanical Characteristics ◽

Angular Displacement ◽

Excitation Frequency ◽

Element Model ◽

Industrial Robots ◽

Axial Distance ◽

Axial Vibration ◽

Cylinder Length ◽

Flexible Parts ◽

Contact Mechanical

Harmonic gear reducer is widely used in industrial robots, aerospace, optics, and other high-end fields. The failure of harmonic gear reducer is mainly caused by the damage of flexible bearing and flexspline of thin-walled vulnerable components. To study the contact mechanical characteristics of flexible components such as flexible bearing and flexspline in harmonic gear reducer, the contact mechanical model of flexible bearing, vibration differential equation of flexspline, and finite element model of each component in harmonic gear reducer were established. Based on the established model of harmonic gear reducer, the influence of the length of flexspline cylinder and the thickness of cylinder bottom on the stress of flexspline is discussed, respectively, and the motion characteristics of flexible bearing are studied. At the same time, the spatial distribution of the displacement of the flexspline and the axial vibration response of the flexspline are studied. The correctness of the model established in this paper is verified by experiments. The results show that the increase of cylinder length can improve the stress of flexspline in harmonic gear reducer; the wall thickness of cylinder bottom mainly affects the stress at the bottom of flexspline but has little effect on the stress of gear ring and smooth cylinder. Along the axis direction of the flexspline, the radial displacement, circumferential displacement, and angular displacement increase linearly with the increase of the axial distance between the cylinder and the bottom. When the excitation frequency is high, the vibration mode of flexspline shell is mainly axial vibration. The research results will provide a theoretical reference for the optimal design of harmonic gear reducer and improving the service life of flexible parts.

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