Contact simulation analysis of double cylindrical asperities using the finite element method

2020 ◽  
Vol 44 (1) ◽  
pp. 72-83
Author(s):  
Lihua Wang ◽  
Liheng Chen ◽  
Yayu Huang ◽  
Tingqiang Yao ◽  
Chunfeng Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Contact Pressure ◽  
Contact Area ◽  
Contact Load ◽  
Single Peak ◽  
Asperity Contact ◽  
The Finite Element Method ◽  
Contact Displacement ◽  
Element Method

To analyze the microcontact characteristics of the rough joint surface obtained by grinding more accurately, a frictionless contact model of double cylindrical asperities was established. The contact characteristics of double cylindrical asperities with different peak distance and different heights were analyzed using the finite element method. The relationship between contact load, contact pressure, contact area, and contact displacement were studied. And the effect of double asperities on the stress state of the cylindrical asperity contact zone was revealed. The results show that, in the elastic contact stage, the contact load, contact stress, contact pressure, and contact area decreased with an increase in the peak distance, and the corresponding values are smaller than that of single peak asperity contact. In the elastoplastic stage, because of the interaction of the double asperities, the change of the contact pressure with the contact displacement on the double asperities contact is larger than the corresponding value of the single peak asperity under the same conditions. The research can be applied into the model of anisotropic interface and provide theoretical foundations for the study on contact characteristics of grinding interface.

Comparative Contact Analysis Study of Finite Element Method Based Deterministic, Simplified Multi-Asperity and Modified Statistical Contact Models

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
A. Megalingam ◽  
M. M. Mayuram
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Rough Surface ◽  
Contact Area ◽  
Model Analysis ◽  
Contact Model ◽  
Contact Load ◽  
Asperity Contact ◽  
Single Asperity ◽  
Contact Models

The study of the contact stresses generated when two surfaces are in contact plays a significant role in understanding the tribology of contact pairs. Most of the present contact models are based on the statistical treatment of the single asperity contact model. For a clear understanding about the elastic-plastic behavior of two rough surfaces in contact, comparative study involving the deterministic contact model, simplified multi-asperity contact model, and modified statistical model are undertaken. In deterministic contact model analysis, a three dimensional deformable rough surface pressed against a rigid flat surface is carried out using the finite element method in steps. A simplified multi-asperity contact model is developed using actual summit radii deduced from the rough surface, applying single asperity contact model results. The resultant contact parameters like contact load, contact area, and contact pressure are compared. The asperity interaction noticed in the deterministic contact model analysis leads to wide disparity in the results. Observing the elastic-plastic transition of the summits and the sharing of contact load and contact area among the summits, modifications are employed in single asperity statistical contact model approaches in the form of a correction factor arising from asperity interaction to reduce the variations. Consequently, the modified statistical contact model and simplified multi-asperity contact model based on actual summit radius results show improved agreement with the deterministic contact model results.

Effect of Traffic Flow on Characteristics of Piezoelectric Harvesting Unit

2014 ◽  
Vol 672-674 ◽  
pp. 902-905 ◽  
Author(s):  
Chun Hua Sun ◽  
Guang Qing Shang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Electric Power ◽  
Traffic Flow ◽  
Contact Pressure ◽  
Green Energy ◽  
The Finite Element Method ◽  
Oil Resources ◽  
Element Method

To protect dwindling coal and oil resources and open up a new way of renewable green energy, the technology of piezoelectric harvesting from pavement is proposed. Effect of traffic flow, including contact pressure and speed of a vehicle, on characteristics of a piezoelectric harvesting unit is discussed with the finite element method. Results show that the harvested electric power is approximately linear with the contact pressure and a vehicle’s speed. The contact pressure takes more effect on the harvested electric power and stress on pavement than the vehicle’s speed. A PHU of 280*280*20mm can harvest about 10mJ electric power when the contact pressure is 0.85MPa. That shows that application of the piezoelectric harvesting unit has very nice optimistic prospects.

Geometry of Ball Seat Valves

2021 ◽  
Author(s):  
Felix Fischer ◽  
Niklas Bauer ◽  
Hubertus Murrenhoff ◽  
Katharina Schmitz
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Contact Pressure ◽  
Contact Area ◽  
Geometric Properties ◽  
Element Method

The macroscopic geometry of ball seat valves is important for the quality of the seal. This works discusses the influence of different geometric properties on the contact area, the contact pressure and their relation to the leakage. The leakage is calculated using the results of finite element method (FEM) calculations and Persson’s percolation based method. The following properties of the seat are examined: the angle, the curvature and the eccentricity.

Finite Element Analysis of Well Pads in Basra Province

2019 ◽  
Vol 7 (1) ◽  
pp. 73-86
Author(s):  
Haider Saad Al-Jubair ◽  
Hiba Abdul Hussein Saheb
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Bearing Capacity ◽  
Contact Pressure ◽  
Cohesionless Soil ◽  
Soil Profiles ◽  
The Finite Element Method ◽  
Safety Factors ◽  
Drilling Rigs ◽  
Element Method

After the year 2003, the oil / gas sector evolved and gained investment. International companies of different origins utilized heavy drilling rigs (to achieve high drilling depths) and entered our region. Meanwhile, some drilling problems were recorded, accompanied by well-pad failure cases. This research aims to study the behavior of well-pads with different geometric configurations, under the effects of drilling rigs with various characteristics, within the Basra province. Four case studies have been selected to represent four fields, namely: Siba, Zubair, West Qurna-2, and Zubair-Mishrif fields. The finite element method is utilized to conduct a stress analysis process, adopting an elastic–plastic constitutive relation for soil, based on Drucker-Prager's yield criterion. The maximum contact pressure applied on soil (under the working loads) is compared to its bearing capacity. When a rigid method is used to calculate the contact pressure, it is compared with the ultimate soil-bearing capacity, as calculated by Reddy and Srinivasan's method for cohesive soils, with allowable bearing capacity taken from the Peck, Hanson, and Thornburn's method for cohesionless soils. The contact pressure calculated via the finite element method is compared with the ultimate soil-bearing capacity calculated using the same method, based on a settlement of 50 mm. The extreme values of the bending moments and shear forces developed in the well-pad sections (under the factored loads), are compared with the section capacities calculated by using the ultimate strength design method. Regarding the geotechnical side, the results indicate insufficient safety factors against soil shear failure for some cases, especially for cohesive soil profiles.  For cohesionless soil profiles, the provided safety factors are sufficient. The finite element method reveals higher contact pressures compared to the conventional rigid method. For cohesionless soil profiles, the Peck, Hanson, and Thornburn's method, gives a bigger safety margin than the finite element method. The immediate settlement values are almost tolerable. Regarding the structural side, it has been identified that a uniform section is adopted for all locations of each pad, for individual wells. In most cases, the provided reinforcing steel is less than the minimum code requirement. This leads to a violation of the section capacity of bending, at least near the cellar. The beam shear capacity is rarely violated. Using strip footings beneath the rig skids, permits utilizing a heavy section that satisfies the requirements of structural safety, without violating the economic considerations.

Simulation of tuning graphene plasmonic behaviors by ferroelectric domains for self-driven infrared photodetector applications

Nanoscale ◽  
2019 ◽  
Vol 11 (43) ◽  
pp. 20868-20875 ◽  
Author(s):  
Junxiong Guo ◽  
Yu Liu ◽  
Yuan Lin ◽  
Yu Tian ◽  
Jinxing Zhang ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Interfacial Effect ◽  
Infrared Photodetector ◽  
The Finite Element Method ◽  
Ferroelectric Domains ◽  
Element Method

We propose a graphene plasmonic infrared photodetector tuned by ferroelectric domains and investigate the interfacial effect using the finite element method.

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