scholarly journals Experimental and Theoretical Analysis on the Dynamic Characteristics of Fused Filament Fabrication Plates

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Shijie Jiang ◽  
Ming Zhan ◽  
Mingyu Sun ◽  
Weibing Dai ◽  
Chunyu Zhao
Keyword(s):  
Dynamic Characteristics ◽  
Material Properties ◽  
Theoretical Basis ◽  
Mechanical Performance ◽  
Dynamic Performance ◽  
Sem Analysis ◽  
Measured Data ◽  
Fused Filament Fabrication ◽  
Dynamic Mechanical

With the increasingly wide application of fused filament fabrication (FFF) technique, the built products are inevitably exposed to dynamic mechanical loading and vibration. However, there has been no systematic study in the literature on understanding and characterization of dynamic mechanical performance for FFF products. In this paper, the dynamic characteristics of FFF plates are quantified, with the effect of different extrusion width taken into account. A dynamic model of the built plate with cantilever boundary conditions is established, and the inherent characteristics are predicted. Modal tests are then performed on these samples to obtain the measured data. Through the comparison between predictions and measurements, the theoretical model is validated. Different extrusion width makes the material properties of the plates different, resulting in different dynamic characteristics. The scanning electron microscopy (SEM) analysis on the samples confirms that the dynamic characteristic is deteriorated as the extrusion width decreases. This present work provides theoretical basis and technical support for further research in improving the dynamic performance of FFF products and helps extend the applications of this technique.

Characterization of discontinuous carbon fiber liquid molded PA-6 composites via strategic placement of additional reinforcements

2018 ◽  
Vol 37 (22) ◽  
pp. 1335-1345 ◽  
Author(s):  
Siddhartha Brahma ◽  
Vikas Patel ◽  
Selvum Pillay ◽  
Haibin Ning ◽  
Vinoy Thomas
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Surface Area ◽  
Mechanical Characterization ◽  
Mechanical Performance ◽  
Total Surface Area ◽  
Sem Analysis ◽  
Average Increase ◽  
Similar Increase

The flexibility of processing PA6-based discontinuous carbon fiber panels using vacuum-assisted resin transfer molding was studied. The ease of incorporating various reinforcements namely baseline, tow in the center of preform, fabric in the center of preform and fabric on the outside as skin was investigated. Mechanical characterization was conducted on all the variations made. There was an average increase of about 3%, 20% and 47% in the tensile properties of tow in the center, fabric in the center and fabric on the outside as skin, respectively, as compared to the baseline. A similar increase in properties was noticed in its flexural and impact strength. The data showed a correlation between the mechanical properties and the total surface area of additional reinforcements used. As the surface area of the reinforcement increased, the mechanical properties increased as well. It also showed that reinforcements on the surface of the preform as a skin performed the best. DMA analysis showed the effect of reinforcement on the storage modulus and tan delta across temperatures ranging from 30°C to 150°C. SEM analysis showed that the fibers and the additional reinforcements were coated with PA6 which translated into consistent mechanical performance.

Modal Analysis for the Column and Spindle Box of TH6213 Boring and Milling Center Machine

2013 ◽  
Author(s):  
Chuanyang Wang ◽  
Xu Wang ◽  
Zhibin Yu
Keyword(s):  
Modal Analysis ◽  
Dynamic Characteristics ◽  
Machine Tools ◽  
Theoretical Basis ◽  
Dynamic Performance ◽  
Machining Accuracy ◽  
Processing Efficiency ◽  
Machine Model ◽  
Solid Edge ◽  
Ansys Workbench

The dynamic characteristics of machine tools have significant effects on their processing quality and processing efficiency. Good dynamic performance of machine is the guarantee of machining accuracy. Modal analysis is the foundation of testing the dynamic characteristics of the machine. Model of Column and spindle box of TH6213 boring and milling center machine are established by using the Solid Edge software. Modal analysis for the column and spindle box was done with ANSYS Workbench to get its natural frequency and mode shape. All this provides the theoretical basis for optimizing the structure.

scholarly journals MATHEMATICAL MODEL OF ESTIMATION THE DYNAMIC PARAMETERS OF MACHINE AND TRACTOR UNIT’S ENGINE UNDER UNSTEAD LOAD

2019 ◽  
Vol 14 (2) ◽  
pp. 106-110 ◽  
Author(s):  
Владимир Медведев ◽  
Vladimir Medvedev ◽  
Станислав Синицкий ◽  
Stanislav Sinickiy
Keyword(s):  
Mathematical Model ◽  
Dynamic Characteristics ◽  
Theoretical Basis ◽  
Theoretical Calculations ◽  
Dynamic Performance ◽  
Transition Process ◽  
Theoretical Studies ◽  
The Mathematical Model ◽  
Regulatory Characteristic ◽  
The Ideal

The article provides an analysis of the existing methods and techniques for assessing the dynamic characteristics of engines of mobile machines, and also presents theoretical calculations for estimating the dynamic performance of an machine and tractor unit’s engine under unsteady load. The proposed mathematical model describes the change in the performance of the engine of machine and tractor unit with a linear law of loading and allows you to compare an engine’s operation at unsteady load with the ideal. The quasi-dynamic characteristic was laid as the theoretical basis for study to assess the dynamic performance of machine and tractor unit’s engine under unsteady load. Comparison of the dynamic performance of engines at unsteady load with ideal performance, which have no dynamic losses. It is proposed to apply the “quasi-dynamic” characteristics. The quasidynamic (ideal) characteristic is called - the change in the performance of machine and tractor unit’s engine, in the transition process, occurring in accordance with the change in the frequency of rotation of the crankshaft on the stationary characteristics. The mathematical model for estimating the dynamic performance of an machine and tractor unit’s engine using a correcting branch with an unsteady load is experimental equations for load buildup. Theoretical relationships have been developed for evaluating the dynamic performance of an engine with an unsteady load on the correcting branch of the regulatory characteristic. Using the proposed theoretical dependences, it is possible to carry out theoretical studies of the effect of load on the dynamic performance of an machine and tractor unit’s engine and determine the total dynamic losses.

scholarly journals Viscoelastic Behavior of Glass-Fiber-Reinforced Silicone Composites Exposed to Cyclic Loading

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1862 ◽  
Author(s):  
Julia Beter ◽  
Bernd Schrittesser ◽  
Bernhard Lechner ◽  
Mohammad Reza Mansouri ◽  
Claudia Marano ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Fiber Orientation ◽  
Mechanical Performance ◽  
Glass Fibers ◽  
Matrix Material ◽  
Viscoelastic Behavior ◽  
Fiber Reinforced ◽  
Step Cycle ◽  
Dynamic Mechanical

The aim of this work was to analyze the influence of fibers on the mechanical behavior of fiber-reinforced elastomers under cyclic loading. Thus, the focus was on the characterization of structure–property interactions, in particular the dynamic mechanical and viscoelastic behavior. Endless twill-woven glass fibers were chosen as the reinforcement, along with silicone as the matrix material. For the characterization of the flexible composites, a novel testing device was developed. Apart from the conventional dynamic mechanical analysis, in which the effect of the fiber orientation was also considered, modified step cycle tests were conducted under tensile loading. The material viscoelastic behavior was studied, evaluating both the stress relaxation response and the capability of the material to dissipate energy under straining. The effects of the displacement rate of the strain level, the amplitude of the strain applied in the loading–unloading step cycle test, and the number of the applied cycles were evaluated. The results revealed that an optimized fiber orientation leads to 30-fold enhanced stiffness, along with 10 times higher bearable stress. The findings demonstrated that tailored reinforced elastomers with endless fibers have a strong influence on the mechanical performance, affecting the structural properties significantly.

Benchmarking of print properties and microstructures of 316L stainless steel DMLS prints

2021 ◽  
Author(s):  
Lucas Gallant ◽  
Amy Hsiao ◽  
Grant McSorley
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Material Properties ◽  
316L Stainless Steel ◽  
Thermal Stresses ◽  
Mechanical Performance ◽  
Grain Structure ◽  
Direct Metal Laser Sintering ◽  
Metal Additive

Abstract Direct metal laser sintering (DMLS) is an established technology in metal additive manufacturing. This complex manufacturing process yields unique as-built material properties that influence mechanical performance and vary with different machine parameters. Part porosity and residual stresses, which lead to part failures, and grain structure, as it relates to mechanical properties and anisotropy of DMLS parts, require investigation for different print settings. This work presents results for density, residual stress, and microstructural inspections on designed test artifacts for the benchmarking of 3D metal printers. Results from printing artifacts on two separate DMLS printer models with default parameters show highly dense parts for both printers, with relative densities above 99.5%. Characterization of residual stress through cantilevered deflection specimens indicates similar resulting thermal stresses developed in both build processes, with deflection averages of 32.48% and 28.09% for the respective machines. Additionally, properties of the test artifact printed after adjusting default machine parameters for equal energy density are characterized.

scholarly journals Crystallization of Random Metallocene-Catalyzed Propylene-Based Copolymers with Ethylene and 1-Hexene on Rapid Cooling

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2091
Author(s):  
Daniela Mileva ◽  
Jingbo Wang ◽  
René Androsch ◽  
Katalee Jariyavidyanont ◽  
Markus Gahleitner ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Metallocene Catalyst ◽  
Nucleating Agent ◽  
Random Copolymers ◽  
Rapid Cooling ◽  
Significant Difference ◽  
Chip Calorimetry ◽  
High Cooling Rates ◽  
Fast Scanning Chip Calorimetry

Propylene-based random copolymers with either ethylene or 1-hexene as comonomer, produced using a metallocene catalyst, were studied regarding their crystallization behaviors, with a focus on rapid cooling. To get an impression of processing effects, fast scanning chip calorimetry (FSC) was used in addition to the characterization of the mechanical performance. When comparing the comonomer type and the relation to commercial grades based on Ziegler–Natta-type catalysts, both an interaction with the catalyst-related regio-defects and a significant difference between ethylene and 1-hexene was observed. A soluble-type nucleating agent was found to modify the behavior, but to an increasingly lesser degree at high cooling rates.

scholarly journals Thermal Performance Analysis of Heat Collection Wall in High-Rise Building Based on the Measurement of Near-Wall Microclimate

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 2023
Author(s):  
Ruixin Li ◽  
Yiwan Zhao ◽  
Gaochong Lv ◽  
Weilin Li ◽  
Jiayin Zhu ◽  
...  
Keyword(s):  
Wind Speed ◽  
Structural Design ◽  
Theoretical Basis ◽  
Thermal Process ◽  
Measured Data ◽  
Passive Heating ◽  
High Rise ◽  
And Performance ◽  
Wall Components ◽  
Near Wall

Near-wall microenvironment of a building refers to parameters such as wind speed, temperature, relative humidity, solar radiation near the building’s façade, etc. The distribution of these parameters on the building façade shows a certain variation based on changes in height. As a technology of passive heating and ventilation, the effectiveness of this application on heat collection wall is significantly affected by the near-wall microclimate, which is manifested by the differences, and rules of the thermal process of the components present at different elevations. To explore the feasibility and specificity of this application of heat collection wall in high-rise buildings, this study uses three typical high-rise buildings from Zhengzhou, China, as research buildings. Periodic measurements of the near-wall microclimate during winter and summer were carried out, and the changing rules of vertical and horizontal microclimate were discussed in detail. Later, by combining these measured data with numerical method, thermal process and performance of heat collection wall based on increasing altitude were quantitatively analyzed through numerical calculations, and the optimum scheme for heat collection wall components was summarized to provide a theoretical basis for the structural design of heat-collecting wall in high-rise buildings.

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