scholarly journals Experimental Study on Electrode Wear of Diamond-Nickel Coated Electrode in EDM Small Hole Machining

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Yu Liu ◽  
Wenjian Wang ◽  
Wenchao Zhang ◽  
Fujian Ma ◽  
Dapeng Yang ◽  
...  
Keyword(s):  
Composite Electrode ◽  
Shape Change ◽  
Matrix Material ◽  
Small Hole ◽  
Tungsten Alloy ◽  
Electrode Wear ◽  
The Matrix ◽  
Tool Shape ◽  
Wear Tool ◽  
Hole Machining

Aiming at the problem of obvious tool length wear and side wear in the small hole processing of EDM, the nickel-coated composite electrode and diamond-nickel-coated composite electrode were prepared by chemical composite coating using brass, copper, molybdenum, and copper-tungsten alloy materials as the matrix material. Comparative experiments of EDM small hole machining using composite tools were carried out on die steel. The effects of nickel-coated composite electrode and diamond-nickel-coated composite electrode on tool length wear, tool side wear, and tool shape change were analyzed. The results show that the diamond-nickel-coated composite electrode can effectively reduce both the length wear and side wear of the electrodes.

Polishing process effect on the image of dispersed precipitates

1984 ◽  
Vol 42 ◽  
pp. 534-535
Author(s):  
C.T. Hu ◽  
C.W. Allen
Keyword(s):  
Matrix Material ◽  
Specimen Preparation ◽  
Second Phase ◽  
Precipitate Particle ◽  
Polishing Process ◽  
Second Phase Particles ◽  
The Matrix ◽  
Surface Profiles ◽  
Thinning Process

One important problem in determination of precipitate particle size is the effect of preferential thinning during TEM specimen preparation. Figure 1a schematically represents the original polydispersed Ni3Al precipitates in the Ni rich matrix. The three possible type surface profiles of TEM specimens, which result after electrolytic thinning process are illustrated in Figure 1b. c. & d. These various surface profiles could be produced by using different polishing electrolytes and conditions (i.e. temperature and electric current). The matrix-preferential-etching process causes the matrix material to be attacked much more rapidly than the second phase particles. Figure 1b indicated the result. The nonpreferential and precipitate-preferential-etching results are shown in Figures 1c and 1d respectively.

Application of cross correlation to HREM images of surfaces

1987 ◽  
Vol 45 ◽  
pp. 754-755
Author(s):  
D. E. Luzzi ◽  
L. D. Marks ◽  
M. I. Buckett
Keyword(s):  
Cross Correlation ◽  
A Priori ◽  
Matrix Material ◽  
Correlation Method ◽  
Accurate Knowledge ◽  
Complex Image ◽  
Fourier Filtering ◽  
The Matrix ◽  
Low Pass ◽  
Data Reduction Technique

As the HREM becomes increasingly used for the study of dynamic localized phenomena, the development of techniques to recover the desired information from a real image is important. Often, the important features are not strongly scattering in comparison to the matrix material in addition to being masked by statistical and amorphous noise. The desired information will usually involve the accurate knowledge of the position and intensity of the contrast. In order to decipher the desired information from a complex image, cross-correlation (xcf) techniques can be utilized. Unlike other image processing methods which rely on data massaging (e.g. high/low pass filtering or Fourier filtering), the cross-correlation method is a rigorous data reduction technique with no a priori assumptions.We have examined basic cross-correlation procedures using images of discrete gaussian peaks and have developed an iterative procedure to greatly enhance the capabilities of these techniques when the contrast from the peaks overlap.

Impact Strength, Flexural Modulus and Wear Rate of PMMA Composites Reinforced by Eggshell Powders

2020 ◽  
Vol 38 (7A) ◽  
pp. 960-966
Author(s):  
Aseel M. Abdullah ◽  
Hussein Jaber ◽  
Hanaa A. Al-Kaisy
Keyword(s):  
Impact Strength ◽  
Wear Rate ◽  
Flexural Modulus ◽  
Matrix Material ◽  
Weight Fraction ◽  
Pure Pmma ◽  
Calcination Process ◽  
The Matrix ◽  
The Impact ◽  
Interface Bond

In the present study, the impact strength, flexural modulus, and wear rate of poly methyl methacrylate (PMMA) with eggshell powder (ESP) composites have been investigated. The PMMA used as a matrix material reinforced with ESP at two different states (including untreated eggshell powder (UTESP) and treated eggshell powder (TESP)). Both UTESP and TESP were mixed with PMMA at different weight fractions ranged from (1-5) wt.%. The results revealed that the mechanical properties of the PMMA/ESP composites were enhanced steadily with increasing eggshell contents. The samples with 5 wt.% of UTESP and TESP additions give the maximum values of impact strength, about twice the value of the pure PMMA sample. The calcination process of eggshells powders gives better properties of the PMMA samples compared with the UTESP at the same weight fraction due to improvements in the interface bond between the matrix and particles. The wear characteristics of the PMMA composites decrease by about 57% with increases the weight fraction of TESP up to 5 wt.%. The flexural modulus values are slightly enhanced by increasing of the ESP contents in the PMMA composites.

scholarly journals Self-Reinforced Nylon 6 Composite for Smart Vibration Damping

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1235
Author(s):  
Bidita Salahuddin ◽  
Rahim Mutlu ◽  
Tajwar A. Baigh ◽  
Mohammed N. Alghamdi ◽  
Shazed Aziz
Keyword(s):  
Matrix Material ◽  
Nylon 6 ◽  
Vibration Damping ◽  
Vibration Energy ◽  
Damping Factor ◽  
Passive Vibration Control ◽  
Reinforced Composite ◽  
Coiled Structure ◽  
The Matrix ◽  
3D Printed

Passive vibration control using polymer composites has been extensively investigated by the engineering community. In this paper, a new kind of vibration dampening polymer composite was developed where oriented nylon 6 fibres were used as the reinforcement, and 3D printed unoriented nylon 6 was used as the matrix material. The shape of the reinforcing fibres was modified to a coiled structure which transformed the fibres into a smart thermoresponsive actuator. This novel self-reinforced composite was of high mechanical robustness and its efficacy was demonstrated as an active dampening system for oscillatory vibration of a heated vibrating system. The blocking force generated within the reinforcing coiled actuator was responsible for dissipating vibration energy and increase the magnitude of the damping factor compared to samples made of non-reinforced nylon 6. Further study shows that the appropriate annealing of coiled actuators provides an enhanced dampening capability to the composite structure. The extent of crystallinity of the reinforcing actuators is found to directly influence the vibration dampening capacity.

Investigation on the Influence of Pressure Terms in a Volume-Averaged Energy Balance in the Modelling of Liquid Composite Moulding Processes

2019 ◽  
Vol 809 ◽  
pp. 480-486
Author(s):  
Rohit George Sebastian ◽  
Christof Obertscheider ◽  
Ewald Fauster ◽  
Ralf Schledjewski
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Energy Balance ◽  
Matrix Material ◽  
Energy Balance Equation ◽  
Manufacturing Processes ◽  
Composite Manufacturing ◽  
Liquid Composite Moulding ◽  
The Matrix ◽  
Computational Fluid Dynamics Cfd

The growing use of composite materials has generated interest in improving and optimising composite manufacturing processes such as Liquid Composite Moulding (LCM). In LCM, dry preforms are placed in a mould and impregnated with the matrix material. The efficiency of filling the moulds can be improved by using Computational Fluid Dynamics (CFD) filling simulations during the design of the mould. As part of an on-going effort to develop a CFD tool for the simulation of LCM processes, a volume averaged energy balance equation has been derived and implemented in a custom OpenFOAM solver. The energy balance is implemented in a custom OpenFOAM solver with and without the pressure terms for comparison with results from RTM experiments. It is found that the pressure terms do not significantly influence the results for LCM processes.

Localized Necking in a Round Tensile Bar with HCP Material Considering Tension-Compression Asymmetry in Plastic Flow

2013 ◽  
Vol 535-536 ◽  
pp. 164-167
Author(s):  
Jonghun Yoon ◽  
Oana Cazacu ◽  
Jung Hwan Lee
Keyword(s):  
Yield Criterion ◽  
Matrix Material ◽  
Ductile Failure ◽  
Material Behavior ◽  
Strength Differential ◽  
The Matrix ◽  
Void Evolution ◽  
Hcp Materials ◽  
Spherical Voids ◽  
Tension Compression Asymmetry

In spite of this progress in predicting ductile failure, the development of macroscopic yield criteria for describing damage evolution in HCP (hexagonal close-packed) materials remains a challenge. HCP materials display strength differential effects (i.e., different behavior in tension versus compression) in the plastic response due to twinning. Cazacu and Stewart [1] developed an analytic yield criterion for a porous material containing randomly distributed spherical voids in an isotropic, incompressible matrix that displays tension-compression asymmetry. The matrix material was taken to obey the isotropic form of the Cazacu et al. [2] yield criterion, which captures the tension-compression asymmetry of the matrix material. In this paper, finite element calculations of a round tensile bar are conducted with the material behavior described by the Cazacu and Stewart [1] yield criterion. The goal of these calculations is to investigate the effect of the tension-compression asymmetry on the necking induced by void evolution and propagation.

Determination of fiber volume fraction in a cured laminate

2021 ◽  
pp. 002199832110112
Author(s):  
Qing Yang Steve Wu ◽  
Nan Zhang ◽  
Weng Heng Liew ◽  
Vincent Lim ◽  
Xiping Ni ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Fiber Volume Fraction ◽  
Evaluation Method ◽  
Volume Fraction ◽  
Matrix Material ◽  
Volume Ratio ◽  
Gravimetric Analysis ◽  
Fiber Volume ◽  
Laser Ultrasonic ◽  
The Matrix

Propagation of ultrasonic wave in Carbon Fiber Reinforced Polymer (CFRP) is greatly influenced by the material’s matrix, resins and fiber volume ratio. Laser ultrasonic broadband spectral technique has been demonstrated for porosity and fiber volume ratio extraction on unidirection aligned CFRP laminates. Porosity in the matrix materials can be calculated by longitudinal wave attenuation and accurate fiber volume ratio can be derived by combined velocity through the high strength carbon fiber and the matrix material with further consideration of porosity effects. The results have been benchmarked by pulse-echo ultrasonic tests, gas pycnometer and thermal gravimetric analysis (TGA). The potentials and advantages of the laser ultrasonic technique as a non-destructive evaluation method for CFRP carbon fiber volume fraction evaluation were demonstrated.

The influence of different geometries of matrix/scaffold on the remodeling process of a bone and bioresorbable material mixture with voids

2015 ◽  
Vol 22 (5) ◽  
pp. 969-987 ◽  
Author(s):  
Ivan Giorgio ◽  
Ugo Andreaus ◽  
Tomasz Lekszycki ◽  
Alessandro Della Corte
Keyword(s):  
Bone Growth ◽  
Matrix Material ◽  
Porous Solids ◽  
Artificial Material ◽  
Matrix Deposition ◽  
Aspect Ratios ◽  
Adopted Model ◽  
The Matrix ◽  
Bioresorbable Material

Since internal architecture greatly influences crucial factors for tissue regeneration, such as nutrient diffusion, cell adhesion and matrix deposition, scaffolds have to be carefully designed, keeping in mind case-specific mechanical, mass transport and biological requirements. However, customizing scaffold architecture to better suit conflicting requirements, such as biological and mechanical ones, remains a challenging issue. Recent advances in printing technologies, together with the synthesis of novel composite biomaterials, have enabled the fabrication of various scaffolds with defined shape and controlled in vitro behavior. Thus, the influence of different geometries of the assemblage of the matrix and scaffold on the remodeling processes of living bone and artificial material should be investigated. To this end, two implant shapes are considered in this paper, namely a circular inclusion and a rectangular groove of different aspect ratios. A model of a mixture of bone tissue and bioresorbable material with voids was used to numerically analyze the physiological balance between the processes of bone growth and resorption and artificial material resorption in a plate-like sample. The adopted model was derived from a theory for the behavior of porous solids in which the matrix material is elastic and the interstices are void of material.

Research of stamping of unequal channel bars. Part 3. Force parameters and shape change of the billet when extruding channels. 1. Kinematic and stress states of the billet

2021 ◽  
pp. 65-71
Author(s):  
A.L. Vorontsov
Keyword(s):  
Plastic Flow ◽  
Complete System ◽  
Shape Change ◽  
Plane Deformation ◽  
System Of Equations ◽  
Flow Rates ◽  
Die Forging ◽  
The Matrix ◽  
Stress States ◽  
Theory Of Plastic Flow

On the basis of the complete system of equations of the theory of plastic flow, the kinematic and stress states of the billet are determined when the channels are extruded under conditions of plane deformation of the misaligned position of the punch and the matrix. Keywords: die forging, extrusion, misaligned position, punch, matrix, plane deformation, plastic flow rates, stresses. [email protected]

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