Hot Drilling of 6082 Aluminium Alloy

2006 ◽  
Author(s):  
L. Santo ◽  
F. Trovalusci ◽  
V. Tagliaferri
Keyword(s):  
Material Properties ◽  
Material Characterization ◽  
Mechanical Characterization ◽  
Thrust Force ◽  
Experimental Tests ◽  
Process Conditions ◽  
Milling Machine ◽  
Drilling Operation ◽  
Drill Diameter ◽  
Twist Drills

In traditional machining drilling is a major and common holemaking process in which lubrication and cooling are very important to improve the machining. The idea proposed in this paper regards the metal heating during the drilling operation by means of an infrared lamp. In this way a reduction in thrust force and torque is expected, since the material properties have been changed. Some experimental tests are carried out on Al 6082 in dry drilling operation, using a conventional milling machine and cobalt-coated HSS twist drills 2.5, 5, 7 mm in diameter. The spindle speeds range from 5000 to 15000 Rpm, the feeds range between 0.0076–0.042 mm/rev, the temperature is varied in the range of 40–140°C. Besides, Flat-top cylinder Indenter for Mechanical Characterization (FIMEC) tests for material characterization are carried out to obtain the yield stress of material varying temperature. The main result is a significant reduction of the thrust force (from 10 to 34% depending on the process conditions). By analysing the data of forces as a function of temperature, a minimum value of force is always found in correspondence of a temperature depending on drill diameter and feed. The influence of each parameter is investigated. The experimental data in terms of force are also correlated to the measured yield stresses to study the influence of material properties on drilling machining. Further study must be developed to investigate the torque, the mechanisms of chip formation and the tool wear.

Delamination-Free Drilling of Composite Laminates

1994 ◽  
Vol 116 (4) ◽  
pp. 475-481 ◽  
Author(s):  
S. Jain ◽  
D. C. H. Yang
Keyword(s):  
Composite Laminates ◽  
Thrust Force ◽  
Tool Geometry ◽  
Elliptical Plate ◽  
Hole Quality ◽  
Drilling Operation ◽  
Twist Drills ◽  
Drill Tool

Composite laminates in significant numbers are rendered unacceptable due to delamination that occurs during the drilling operation. Thrust generated during the drilling operation is identified as responsible for delamination. Expressions developed for critical thrusts and critical feed rates, by modeling the delamination zone as an elliptical plate in unidirectional laminates, appear to be fairly accurate. It has been demonstrated that the critical thrusts and feed rates obtained for unidirectional laminates can be conservatively used for multi-directional laminates. With regard to the tool geometry, the chisel edge width appears to be the single most important factor contributing to the thrust force and hence delamination. A diamond-impregnated tubular drill tool was designed and tested. This tool resulted in a much smaller thrust and much better hole quality as compared with the standard twist drills.

Mechanical Characterization of Assemblies Bonded With Pressure-Sensitive Adhesives (PSAs)

2015 ◽  
Author(s):  
Hao Huang ◽  
Abhijit Dasgupta ◽  
Ehsan Mirbagheri ◽  
Srini Boddapati
Keyword(s):  
Mechanical Behavior ◽  
Failure Modes ◽  
Mechanical Characterization ◽  
Bonding Temperature ◽  
Process Conditions ◽  
Second Phase ◽  
Loading Conditions ◽  
Stress Strain ◽  
Strain Behavior ◽  
Pressure Sensitive

The focus of this paper is on the stress-strain behavior and creep response of a pressure-sensitive adhesive (PSA) with and without carrier layers. This study consists of two phases. The first phase focuses on understanding of the effects of fabrication profiles, including bonding pressure, bonding temperature, bonding time, and aging time, on the PSA joint strength. This part of the study is used to identify an acceptable bonding and aging conditions for manufacturing a robust PSA bonded assembly. Specimens fabricated with this selected set of bonding process conditions are then used for mechanical characterization. The second phase focuses on the assembly’s mechanical behavior (stress-strain behavior and the creep curves) under different loading conditions, including loading stress, loading rate, and loading temperature. The mechanical behavior of PSA bonded assemblies is affected not only by the loading conditions, but also by the assembly architecture. The mechanical behaviors and failure modes of PSAs with and without carrier layers are compared. The reasons for these differences are also discussed.

scholarly journals Mechanical characterization of concrete block used on infill masonry panels

2018 ◽  
Vol 9 (3) ◽  
pp. 281-295 ◽  
Author(s):  
Patricia Raposo ◽  
André Furtado ◽  
António Arêde ◽  
Humberto Varum ◽  
Hugo Rodrigues
Keyword(s):  
Mechanical Characterization ◽  
Experimental Tests ◽  
Concrete Block ◽  
Masonry Walls ◽  
Compression Tests ◽  
Content Type ◽  
Average Resistance ◽  
Concrete Blocks ◽  
Simple Compression ◽  
Infill Masonry

Purpose The infill masonry walls in recent worldwide earthquakes have shown that it is necessary to conduct further studies to characterize the behavior of existing buildings and, in particular, of infill masonry walls under seismic activity. The lack of characterization studies of infill walls made by concrete blocks justifies the investigation reported herein, which includes experimental tests on sample sets to evaluate the mechanical properties of masonry components (units and mortar) and assemblages (wallets) made with masonry units from Faial. For the later, normal compressive, diagonal tensile/shear and out-of-plane flexural strengths were obtained according to standard procedures, the results of which are presented in the manuscript. The paper aims to discuss these issues. Design/methodology/approach One experimental campaign was conducted with the aim to mechanically characterize concrete blocks masonry samples. Several experimental tests were carried out in full-scale masonry concrete wallets according to the constructive methodology used. Findings Based on the data obtained from the mechanical characterization tests of the concrete masonry blocks, it can be seen that under simple compression, the masonry specimens’ average resistance is about 6 times superior than the average resistance to diagonal shear/tension, while the stiffness is almost doubled. In simple compression tests, it was observed that the masonry specimens cracked in areas of higher drilling of the blocks. In the tensile tests by diagonal compression, it was found that the test specimens were mainly fissured by the block/mortar joint interfaces, following the delineation of settlement and top joints. Originality/value There are no experimental results available in the literature for this type of bricks that can contribute to the development of numerical studies.

Predicting Drilling Forces and Delamination in GFRP Laminates using Fuzzy Logic

2014 ◽  
Vol 1 (2) ◽  
pp. 32-43
Author(s):  
Vikas Dhawan ◽  
Sehijpal Singh ◽  
Inderdeep Singh
Keyword(s):  
Thrust Force ◽  
Cutting Speed ◽  
Fuzzy Rule ◽  
Work Piece ◽  
Fiber Reinforced ◽  
Reinforced Plastics ◽  
Glass Fiber Reinforced ◽  
Drill Diameter ◽  
Solid Carbide ◽  
Experimental Values

Drilling of fiber reinforced plastics is necessary in order to assemble complex/intricate composite products. Drilling induced damage leads to high percentage of part rejection and reduced product efficiency and life. The thrust force and torque have been found to be the important factors influencing damage. In the present research endeavor, an attempt has been made to develop a fuzzy rule based model for predicting thrust force, torque and drilling induced delamination during drilling of glass fiber reinforced epoxy plastics (GFREP). The work piece material, drill geometry, drill diameter, feed and cutting speed have been considered as the five input parameters. Four types of solid carbide drills namely 8 facet, 4 facet, parabolic and jodrill of 4 mm and 8 mm size were used to make holes in UD-GFREP and { (0/90) /0]s GFREP laminates at three different levels of speed and feed. The results of the predictive model have been found to be in good agreement with experimental values.

Central Bursting and Optimal Die Profile for Axisymmetric Extrusion

1996 ◽  
Vol 118 (4) ◽  
pp. 579-584 ◽  
Author(s):  
N. Venkata Reddy ◽  
P. M. Dixit ◽  
G. K. Lal
Keyword(s):  
Material Properties ◽  
Process Conditions ◽  
Simple Criterion ◽  
Geometric Conditions ◽  
Die Profile ◽  
Good Agreement

A simple criterion for predicting the initiation of central burst in extrusion is proposed. The geometric conditions to avoid central bursting are predicted by using the proposed criterion under various process conditions and material properties. The optimal die profiles which minimize the extrusion power are also obtained for various process conditions. The mixed (pressure-velocity) formulation is used along with the Householder method to solve the resulting equations. It is shown that the optimal die profiles satisfy the conditions for prevention of central burst. The predictions based on the proposed criterion are in good agreement with the experimental observations and are in conformity with the results published earlier.

Effects of Texture on Thermoelectric Power in Ti-6Al-4V

2006 ◽  
Author(s):  
Hector Carreon
Keyword(s):  
Thermoelectric Power ◽  
Material Properties ◽  
Material Characterization ◽  
Grain Structure ◽  
Power Dependence ◽  
Anisotropic Behavior ◽  
Nondestructive Technique ◽  
Parallel Direction ◽  
Polycrystalline Microstructure ◽  
Power Measurements

Ti-6A1-4V alloy exhibits a very strong anisotropic texture caused by the existence of a preferred crystallographic orientation in the polycrystalline microstructure. This crystallographic alignment can result in anisotropic behavior of the material so that the material properties are different depending on whether they are measured in perpendicular or parallel direction. In addition to this morphological anisotropy, due to the dominantly hexagonal grain structure, the Ti-6A1-4V alloy also exhibited a substantial thermoelectric anisotropy. This study was conducted to investigate the effect of thermoelectric anisotropy on the thermoelectric power measurements in a highly textured Ti-6A1-4V specimen using a completely nondestructive technique based on the Seebeck effect. The result shows the thermoelectric power dependence associated with texturing and the macroscopic grain structure in a rolled Ti-6A1-4V specimen, which was annealed at 710°C for 2 hours and slowly cooled. The measurements clearly demonstrated that the intrinsic sensitivity of the thermoelectric contact technique is a very useful tool that could be exploited for quantitative nondestructive (QND) material characterization.

scholarly journals Prospects for defect engineering in Cu2ZnSnS4 solar absorber films

2020 ◽  
Vol 8 (31) ◽  
pp. 15864-15874
Author(s):  
Katharina Rudisch ◽  
Alexandra Davydova ◽  
Lars Riekehr ◽  
Joakim Adolfsson ◽  
Luciano Quaglia Casal ◽  
...  
Keyword(s):  
Thin Films ◽  
Material Properties ◽  
Process Conditions ◽  
Defect Engineering ◽  
Solar Absorber ◽  
New Approaches

Composition spread Cu2ZnSnS4 thin films unveil the complicated interplay between process conditions and material properties, pointing to new approaches towards defect engineering.

scholarly journals Two-Phase Linear Hybrid Reluctance Actuator with Low Detent Force

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5162
Author(s):  
Jordi Garcia-Amorós ◽  
Marc Marín-Genescà ◽  
Pere Andrada ◽  
Eusebi Martínez-Piera
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Permanent Magnets ◽  
Thrust Force ◽  
Experimental Tests ◽  
Force Density ◽  
Two Phase ◽  
Element Analysis ◽  
Switched Reluctance ◽  
Detent Force

In this paper, a novel two-phase linear hybrid reluctance actuator with the double-sided segmented stator, made of laminated U cores, and an interior mover with permanent magnets is proposed. The permanent magnets are disposed of in a way that increases the thrust force of a double-sided linear switched reluctance actuator of the same size. To achieve this objective, each phase of the actuator is powered by a single H-bridge inverter. To reduce the detent force, the upper and the lower stator were shifted. Finite element analysis was used to demonstrate that the proposed actuator has a high force density with low detent force. In addition, a comparative study between the proposed linear hybrid reluctance actuator, linear switched reluctance, and linear permanent magnet actuators of the same size was performed. Finally, experimental tests carried out in a prototype confirmed the goals of the proposed actuator.

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