scholarly journals Development of spring torsion bar type negative stiffness damping device and applied research

2021 ◽  
Vol 2137 (1) ◽  
pp. 012040
Author(s):  
XinKe Song ◽  
DeMin Chen ◽  
QingMing Long ◽  
BaoHua Qu
Keyword(s):  
Mechanical Performance ◽  
Simulation Analysis ◽  
Vibration Reduction ◽  
Three Dimensional ◽  
Vibration Damping ◽  
Negative Stiffness ◽  
Technical Solution ◽  
Vibration Source ◽  
Vibration Simulation ◽  
Torsion Bar

Abstract Mini-tiller is the most commonly used machine for agricultural production in hilly areas of our country the traditional micro-tiller will produce strong vibration during the working process, which will cause physical injury to the operator while reducing the reliability of the micro-tiller. In response to this problem, a technical solution for arranging a spring torsion bar type negative stiffness vibration damping device on the tiller was proposed, and a spring torsion bar type vibration damping device with stable mechanical performance, economical and practical, and negative stiffness characteristics was developed. A mathematical model of the vibration source of the micro-tiller was established to analyze the vibration parameters of the micro-tiller. On this basis, SolidWorks is used to carry out three-dimensional modeling of the tiller and the vibration reduction device, and Adams is used for vibration simulation analysis. The vibration parameter curve before and after the addition of the vibration reduction device at the handle of the tiller is collected and mathematically analyzed. The results show that the spring torsion bar type negative stiffness damping device has a good damping effect, and the damping rate for displacement in the x, y, and z directions are all above 30%.

The Simulation Analysis on Vibration of a Museum Building Nearby Induced by Urban Subway Transit

2011 ◽  
Vol 243-249 ◽  
pp. 3427-3431 ◽  
Author(s):  
Lian Xu Shi ◽  
Nan Zhang
Keyword(s):  
Finite Element ◽  
Simulation Analysis ◽  
Vibration Reduction ◽  
Three Dimensional ◽  
Element Model ◽  
Subway Tunnel ◽  
Vibration Acceleration ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Control Limits

The museum is adjacent to a subway tunnel, cultural relics may be damaged by the vibration induced by subway transit, so the vibration influence of museum must be strictly controlled. By building the three-dimensional finite element model which contains floating slab and isolation ditch, the calculation and analysis for each layer vibration acceleration value of the museum caused by the subway will be done. The results of the study indicate that vibration acceleration value were not more than vibration control limits, vibration reduction and isolation reach the predetermined purpose.

Finite Element Simulation Analysis of Concrete Hyperbolic Arch Dam

2014 ◽  
Vol 488-489 ◽  
pp. 581-584
Author(s):  
Zhen Ren
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Mechanical Performance ◽  
Simulation Analysis ◽  
Three Dimensional ◽  
Arch Dam ◽  
Operating Process ◽  
Element Simulation ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Arch dam is a water retaining structure which has beautiful bodily form and reasonable structure form, in recent years, arch dam has been widely used. This paper adopts finite element method to carry out three-dimensional finite element simulation analysis for Haierwa reservoir concrete hyperbolic arch dam, researching variation law of the dams stress and displacement in operating process. Research results show that, Haierwa reservoir concrete hyperbolic arch dam is reasonable structure, good mechanical performance, every index meets the requirements for design.

scholarly journals Is Micro X-ray Computer Tomography a Suitable Non-Destructive Method for the Characterisation of Dental Materials?

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1271
Author(s):  
Andreas Koenig ◽  
Leonie Schmohl ◽  
Johannes Scheffler ◽  
Florian Fuchs ◽  
Michaela Schulz-Siegmund ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Computer Tomography ◽  
Mechanical Performance ◽  
Dental Materials ◽  
Three Dimensional ◽  
X Rays ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Multiple Measurements ◽  
High Doses

The aim of the study was to investigate the effect of X-rays used in micro X-ray computer tomography (µXCT) on the mechanical performance and microstructure of a variety of dental materials. Standardised bending beams (2 × 2 × 25 mm3) were forwarded to irradiation with an industrial tomograph. Using three-dimensional datasets, the porosity of the materials was quantified and flexural strength was investigated prior to and after irradiation. The thermal properties of irradiated and unirradiated materials were analysed and compared by means of differential scanning calorimetry (DSC). Single µXCT measurements led to a significant decrease in flexural strength of polycarbonate with acrylnitril-butadien-styrol (PC-ABS). No significant influence in flexural strength was identified for resin-based composites (RBCs), poly(methyl methacrylate) (PMMA), and zinc phosphate cement (HAR) after a single irradiation by measurement. However, DSC results suggest that changes in the microstructure of PMMA are possible with increasing radiation doses (multiple measurements, longer measurements, higher output power from the X-ray tube). In summary, it must be assumed that X-ray radiation during µXCT measurement at high doses can lead to changes in the structure and properties of certain polymers.

scholarly journals Investigations of polyethylene of raised temperature resistance service performance using autoclave test under sour medium conditions

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 346-354
Author(s):  
Guoquan Qi ◽  
Hongxia Yan ◽  
Dongtao Qi ◽  
Houbu Li ◽  
Lushi Kong ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Mechanical Performance ◽  
Three Dimensional ◽  
Service Performance ◽  
Degree Of Branching ◽  
Temperature Resistance ◽  
Temperature Conditions ◽  
Dimensional Network ◽  
Gas Medium ◽  
Better Than

Abstract The chapter deals with the performance evaluation of the polyethylene of raised temperature resistance (PE-RT) and polyethylene (PE) using autoclave test under sour oil and gas medium conditions. The analyses of performance changes showed that PE-RT has good media resistance at 60°C. As the temperature increases, its mechanical properties decrease, accompanied by an increase in weight. Comparative analyses showed that no matter what temperature conditions are, PE-RT media resistance is better than PE80. The better media resistance of PE-RT depends on its higher degree of branching. Short branches are distributed between the crystals to form a connection between the crystals, thereby improving its heat resistance and stress under high-temperature conditions. PE-RT forms an excellent three-dimensional network structure through copolymerization, ensuring that it has better media resistance than PE80. However, the mechanical performance will be attenuated due to the high service temperature.

Simulation Analysis of Pneumatic on-off Pressure Mechanism on Printing Press

2010 ◽  
Vol 154-155 ◽  
pp. 1481-1484 ◽  
Author(s):  
Jun Zhong Guo ◽  
Jun Ping Yang
Keyword(s):  
Kinematic Analysis ◽  
Simulation Analysis ◽  
Angular Displacement ◽  
Three Dimensional ◽  
Printing Press ◽  
Work Demand ◽  
Analysis Process ◽  
Adams Software ◽  
Important Basis

The on-off pressure mechanism has an important function to the printing press, the quality of which concerns the working performance of the printing machine and the quality of printed products directly. In this paper, the pneumatic on-off pressure mechanism is discussed; the work demand of order on-off pressure is analyzed. In addition, the three-dimensional digital model and the kinematic analysis process can be achieved on the basis of ADAMS software. What’s more, the on pressure value in the process of on pressure is derived from the kinematic analysis. Lastly, the relation between the motion of on-off pressure mechanism and cylinder’s angular displacement is analyzed, an important basis to the on-off pressure mechanism’s optimal design will be provided.

Study on Feed Offset in Elliptical Vibration Cutting

2014 ◽  
Vol 490-491 ◽  
pp. 600-606
Author(s):  
Jie Qiong Lin ◽  
Jin Guo Han ◽  
Dan Jing ◽  
Xian Jing
Keyword(s):  
Surface Topography ◽  
Surface Quality ◽  
Simulation Analysis ◽  
Three Dimensional ◽  
Curved Surface ◽  
Elliptical Vibration Cutting ◽  
Vibration Cutting ◽  
Elliptical Vibration ◽  
Tool Edge

Elliptical vibration cutting (EVC) process and three dimensional cutting surfaces are analyzed in this paper to understand the formation of surface topography. The model of EVC surface topography is established based on curved surface remove function under the assumption that the tool edge is sharp enough. And simulation analysis of surface topography is conducted with different feed offset ratios. Results indicate that RMS change with feed offset ratios λ. The range of RMS is larger when feed offset ratio ranges from both 0 to 0.4 and 0.6 to 1, while the range is smaller when feed offset ratio changes from 0.4 to 0.6. Whats more, RMS reaches the minimum when feed offset ratio is 0.5. The present research provides some references for reducing the height of vibration ripples and improving EVC surface quality.

The Method for Determining the Vibration-Damping Elements for the Mechanical System to Obtain the Desired Amplitude Value

2014 ◽  
Vol 657 ◽  
pp. 644-648 ◽  
Author(s):  
Andrzej Dymarek ◽  
Tomasz Dzitkowski
Keyword(s):  
Mechanical System ◽  
Dynamic Characteristics ◽  
Vibration Reduction ◽  
Mechanical Systems ◽  
Vibration Damping ◽  
Displacement Velocity ◽  
Synthesis Methods ◽  
Resonance Frequencies

The paper presents the use of synthesis methods to determine the parameters of passive vibration reduction in mechanical systems. Passive vibration reduction in a system is enabled by units called dampers whose values are determined on the basis of the method formulated and formalized by the authors. The essence of the method are, established at the beginning of a task, dynamic characteristics in the form of the resonance and anti-resonance frequencies, and amplitudes of displacement, velocity or acceleration of vibration.

scholarly journals High strength and conductive hydrogel with fully interpenetrated structure from alginate and acrylamide

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 391-397
Author(s):  
Tao Liu ◽  
Ripeng Zhang ◽  
Jianzhi Liu ◽  
Ling Zhao ◽  
Yueqin Yu
Keyword(s):  
Mechanical Performance ◽  
Three Dimensional ◽  
High Strength ◽  
Extreme Environment ◽  
Natural Polymers ◽  
Conductive Hydrogel ◽  
Wide Range ◽  
Interpenetrated Structure ◽  
Conductive Hydrogels ◽  
Conductive Properties

Abstract Highly stretched and conductive hydrogels, especially synthetized from natural polymers, are beneficial for highly stretched electronic equipment which is applied in extreme environment. We designed and prepared robust and tough alginate hydrogels (GMA-SA-PAM) using the ingenious strategy of fully interpenetrating cross-linking, in which the glycidyl methacrylate (GMA) was used to modify sodium alginate (SA) and then copolymerized with acrylamide (AM) and methylenebisacrylamide (BIS) as cross-linkers. The complete cross-linked structures can averagely dissipate energy and the polymer structures can maintain hydrogels that are three-dimensional to greatly improve the mechanical performance of hydrogels. The GMA-SA-PAM hydrogels display ultra-stretchable (strain up to ∼407% of tensile strain) and highly compressible (∼57% of compression strain) properties. In addition, soaking the GMA-SA-PAM hydrogel in 5 wt% NaCl solution also endows the conductivity of the hydrogel (this hydrogel was named as GSP-Na) with excellent conductive properties (5.26 S m−1). The GSP-Na hydrogel with high stability, durability, as well as wide range extent sensor is also demonstrated by researching the electrochemical signals and showing the potential for applications in wearable and quickly responded electronics.

Simulation analysis of mechanical performance of laser catheter in ELCA operation

2021 ◽  
Author(s):  
Lei Su ◽  
Bowen Liao ◽  
Yichun Wang ◽  
Hongzhang He ◽  
Han Wu ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Simulation Analysis
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