Vibration compaction process model for rockfill materials considering viscoelastic-plastic deformation

2021 ◽  
Vol 131 ◽  
pp. 103889
Author(s):  
Zaizhan An ◽  
Tianyun Liu ◽  
Qinglong Zhang ◽  
Zhaosheng Zhang ◽  
Zehua Huangfu ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Process Model ◽  
Compaction Process ◽  
Rockfill Materials ◽  
Vibration Compaction

Dynamic optimization of compaction process for rockfill materials

2020 ◽  
Vol 110 ◽  
pp. 103038 ◽  
Author(s):  
Zaizhan An ◽  
Tianyun Liu ◽  
Zhaosheng Zhang ◽  
Qinglong Zhang ◽  
Zehua Huangfu ◽  
...  
Keyword(s):  
Dynamic Optimization ◽  
Compaction Process ◽  
Rockfill Materials

Application Analysis of Vibrating Wheel-Soil Model Based on ABAQUS

2013 ◽  
Vol 644 ◽  
pp. 366-369 ◽  
Author(s):  
Yuan Wen Cao ◽  
Liang Xiang ◽  
Li Ying Ma ◽  
Ze Jun Li
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Roller Compaction ◽  
Construction Technology ◽  
Compaction Process ◽  
Element Analysis ◽  
Soil Model ◽  
Application Analysis ◽  
Vibration Compaction ◽  
Theory Base

Vibration wheel and soil model is established by a finite element analysis software ABAQUS. Simulate and analyze the vibration compaction process with different vibration force and different speed, the result showed that the finite element model is a good simulation of the vibrating compaction process. It is a theory base of vibratory roller construction technology and prediction of vibratory roller compaction effect.

Densification Mechanism of Warm Compaction for Iron-Based Powder Materials

2007 ◽  
Vol 534-536 ◽  
pp. 261-264
Author(s):  
Sheng Guan Qu ◽  
Yuan Yuan Li ◽  
Wei Xia ◽  
Wei Ping Chen
Keyword(s):  
Plastic Deformation ◽  
Powder Materials ◽  
Force Component ◽  
Compaction Process ◽  
Densification Mechanism ◽  
Warm Compaction ◽  
Different Temperatures ◽  
Iron Based ◽  
Compaction Processes ◽  
Insight Into

An apparatus measuring changes of various forces directly and continuously was developed by a way of direct touch between powders and transmitting force component, which can be used to study forces state of powders during warm compaction. Using the apparatus, warm compaction processes of iron-based powder materials containing different lubricants at different temperatures were studied. Results show that densification of the powder materials can be divided into four stages, in which powder movement changes from robustness to weakness, while its degree of plastic deformation changes from weakness to robustness. The proposed densification mechanism may provide an insight into understanding of warm compaction process.

On the use of HCP and FCC RVE structures in the simulation of powder compaction

2018 ◽  
Vol 53 (5) ◽  
pp. 338-352
Author(s):  
Bao Zhang ◽  
Idris K Mohammed ◽  
Yi Wang ◽  
Daniel S Balint
Keyword(s):  
Plastic Deformation ◽  
Relative Density ◽  
Numerical Models ◽  
Powder Compaction ◽  
Initial Contact ◽  
Powder Materials ◽  
Face Centered Cubic ◽  
Compaction Process ◽  
Regular Packing ◽  
Rate Dependent

Use of hexagonal close packed and face centered cubic structures to simulate powder compaction reveals that plastic deformation is effective in reducing porosity until a relative density of 0.96, beyond which a drastic rise in pressure is required. The compaction process can be divided into three phases demarcated by relative densities of 0.8 and 0.92, characterized, respectively, by local yielding around the initial contact point, coalescence of locally yielded zones and full plastic flow to reduce pores. The macroscopic yield behaviour of the powder assembly in the present work agrees reasonably with analytical and numerical models such as the Storåkers-Fleck-McMeeking model and multi-particle finite element model. It is found that for rate-dependent powder materials, the compaction process is noticeably rate dependent from a relative density of 0.85. Although a regular packing of powders is unrealistic, the understanding gained from a regular packing model provides insight into the role that plastic deformation plays during powder compaction.

Influencing Factors Research on Compaction Effect of Coarse Rubber Granule Asphalt Mixture

2012 ◽  
Vol 466-467 ◽  
pp. 157-160
Author(s):  
Zhuo Zhang
Keyword(s):  
Influencing Factors ◽  
Orthogonal Experiment ◽  
Influencing Factor ◽  
Asphalt Mixture ◽  
Combined Method ◽  
Rubber Content ◽  
Compaction Process ◽  
Dry Process ◽  
Vibration Compaction ◽  
Vibration Time

Dry process was taken by coarse rubber granule replacing coarse aggregate of the same volume. By an orthogonal experiment, a combined method of vibration compaction and Marshall compaction was used to study main influencing factors on compaction effect of coarse rubber granule asphalt mixture, making voidage as guidepost. The experiment results show that the most prominent influencing factor is rubber content, secondly the influencing factors are compaction temperature, vibration frequency and vibration time, the least is compaction times. An optimal compaction process for the coarse rubber granule asphalt mixture is put forward.

Numerical Simulation of Rolling Compaction Process for Rockfill Dam by Particle Flow Code

2012 ◽  
Vol 170-173 ◽  
pp. 2000-2003 ◽  
Author(s):  
Yang Liu ◽  
Xiao Zhu Li
Keyword(s):  
Numerical Simulation ◽  
Particle Flow ◽  
Particle Flow Code ◽  
Test Results ◽  
Compaction Process ◽  
Rockfill Dam ◽  
Field Compaction ◽  
Vibration Compaction ◽  
Three Stages

Based on field compaction test of Nuozhadu I district rockfill engineering, numerical simulation was conducted to study the rolling compaction (RC) process using Particle Flow Code (PFC). Effects of different particle content to the quality of dam filling were discussed based on both numerical and filed test results. Numerical results also revealed the particle movement of the rockfill, the density of the formation mechanism and compaction characteristics during the RC process. Field test and simulated results both indicated that the RC process can be divided into three stages of vibration compaction, void filling and the unloading rebound phase

Sem Examinations of Glass Knives

1970 ◽  
Vol 28 ◽  
pp. 282-283
Author(s):  
J. Temple Black
Keyword(s):  
Plastic Deformation ◽  
Tensile Loading ◽  
Resultant Force ◽  
Stress Concentrations ◽  
Edge Chipping ◽  
Surface Flaws ◽  
Edge Defects ◽  
Microscopic Surface

There are two types of edge defects common to glass knives as typically prepared for microtomy purposes: 1) striations and 2) edge chipping. The former is a function of the free breaking process while edge chipping results from usage or bumping of the edge. Because glass has no well defined planes in its structure, it should be highly resistant to plastic deformation of any sort, including tensile loading. In practice, prevention of microscopic surface flaws is impossible. The surface flaws produce stress concentrations so that tensile strengths in glass are typically 10-20 kpsi and vary only slightly with composition. If glass can be kept in compression, wherein failure is literally unknown (1), it will remain intact for long periods of time. Forces acting on the tool in microtomy produce a resultant force that acts to keep the edge in compression.

Stereo Electron Microscopy Applied to High Resolution Freeze-Etch Replicas

1970 ◽  
Vol 28 ◽  
pp. 306-307
Author(s):  
L. Andrew Staehelin
Keyword(s):  
Electron Microscopy ◽  
Plastic Deformation ◽  
High Resolution ◽  
Smooth Surfaces ◽  
Small Particles ◽  
Membrane Surfaces ◽  
Wide Acceptance ◽  
New Information ◽  
Number Of Particles ◽  
Small Holes

Freeze-etched membranes usually appear as relatively smooth surfaces covered with numerous small particles and a few small holes (Fig. 1). In 1966 Branton (1“) suggested that these surfaces represent split inner mem¬brane faces and not true external membrane surfaces. His theory has now gained wide acceptance partly due to new information obtained from double replicas of freeze-cleaved specimens (2,3) and from freeze-etch experi¬ments with surface labeled membranes (4). While theses studies have fur¬ther substantiated the basic idea of membrane splitting and have shown clearly which membrane faces are complementary to each other, they have left the question open, why the replicated membrane faces usually exhibit con¬siderably fewer holes than particles. According to Branton's theory the number of holes should on the average equal the number of particles. The absence of these holes can be explained in either of two ways: a) it is possible that no holes are formed during the cleaving process e.g. due to plastic deformation (5); b) holes may arise during the cleaving process but remain undetected because of inadequate replication and microscope techniques.

Plastic Deformation in Microtomed Sections

1971 ◽  
Vol 29 ◽  
pp. 458-459
Author(s):  
J. Temple Black
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Applied Stress ◽  
Elastic Strain ◽  
High Strain ◽  
Tool Material ◽  
Cutting Edge ◽  
Material Structure ◽  
Geometrical Constraints

The output of the ultramicrotomy process with its high strain levels is dependent upon the input, ie., the nature of the material being machined. Apart from the geometrical constraints offered by the rake and clearance faces of the tool, each material is free to deform in whatever manner necessary to satisfy its material structure and interatomic constraints. Noncrystalline materials appear to survive the process undamaged when observed in the TEM. As has been demonstrated however microtomed plastics do in fact suffer damage to the top and bottom surfaces of the section regardless of the sharpness of the cutting edge or the tool material. The energy required to seperate the section from the block is not easily propogated through the section because the material is amorphous in nature and has no preferred crystalline planes upon which defects can move large distances to relieve the applied stress. Thus, the cutting stresses are supported elastically in the internal or bulk and plastically in the surfaces. The elastic strain can be recovered while the plastic strain is not reversible and will remain in the section after cutting is complete.

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