scholarly journals Fracture energy for orthogonal cutting in unidirectional CFRP at different cutting directions

2022 ◽  
Vol 1217 (1) ◽  
pp. 012011
Author(s):  
A N Amir ◽  
H Ghazali ◽  
H Wang ◽  
L Ye ◽  
N A Fadi ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Fracture Energy ◽  
Cutting Forces ◽  
Orthogonal Cutting ◽  
Rake Angle ◽  
Balance Model ◽  
Fracture Mechanisms ◽  
Cutting Depth ◽  
Fibre Direction ◽  
Cfrp Laminate

Abstract A unidirectional carbon fibre reinforced polymer (CFRP) laminate is a composite material made up of strong parallel carbon fibres incorporated in a polymer matrix such as epoxy to provide high stiffness and strength in the fibre direction of the laminate. Unfortunately, the interlaminar or intralaminar plane of this material has a low resistance to damages as the fracture toughness of a unidirectional CFRP laminate is related to the energy dissipation during the orthogonal cutting. The aim of this study is on cutting a unidirectional CFRP along the longitudinal or transverse directions, characterizing orthogonal cutting forces and the related fracture energy. Orthogonal cutting is performed using braised carbide tools for a range of cutting depth of 10-100 ³m with a rake angle of 30° to quantify the cutting forces and to observe the fracture mechanisms. The fibre orientations have a significant impact on surface bouncing-back. For some fibre orientations, the energy balance model is applicable, deducting the reasonable value of fracture toughness due to high normal force (F t). Fibre subsurface damage and cutting forces during cutting are found to be strongly influenced by the cutting depth. The input energy of cutting is released in form of new surface energy, fibre breakage, high bending energy, and chip fracture energy.

Cutting Forces in Orthogonal Cutting of Unidirectional GFRP Composites

1996 ◽  
Vol 118 (3) ◽  
pp. 419-425 ◽  
Author(s):  
G. Caprino ◽  
L. Nele
Keyword(s):  
Size Effect ◽  
Cutting Forces ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Rake Angle ◽  
Depth Of Cut ◽  
Vertical Force ◽  
Fibre Direction ◽  
Unit Width ◽  
Relief Angle

The results of orthogonal cutting tests carried out on unidirectional glass fiber reinforced plastic composites, using HSS tools, are presented and discussed. During the tests, performed on a milling machine at very low cutting speed to avoid thermal effects, the cutting speed was held constant and parallel to the fibre direction. Three parameters, namely the tool rake angle α, the tool relief angle γ, and the depth of cut t, were varied. According to the experimental results, the horizontal force per unit width, Fhu, undergoes a dramatic decrease, never verified for metals, with increasing α. Besides, Fhu is only negligibly affected by the relief angle, and linearly increases with t. Similarly to metals, an effect of the depth of cut on the specific energy (size effect) is found also for composites. However, the presented results indicate that the size effect can be analytically modeled in a simple way in the case of composites. The vertical force per unit width, Fvu, exhibits a marked reduction when the relief angle is increased. Fvu, is also very sensitive to the rake angle: the lower α the higher is Fvu. It is shown that this behavior probably reflects a strong influence of the rake angle on the forces developing at the flank. A linear dependence of the vertical force on the depth of cut is also demonstrated. Finally, the experimental data are utilized to obtain empirical formulae, allowing an approximate evaluation of cutting forces.

Finite Element and Experimental Analysis of Edge Defects Formation during Orthogonal Cutting of SiCp/Al Composites

2012 ◽  
Vol 500 ◽  
pp. 146-151 ◽  
Author(s):  
Ning Hou ◽  
Li Zhou ◽  
Shu Tao Huang ◽  
Li Fu Xu
Keyword(s):  
Finite Element ◽  
Chip Formation ◽  
Defect Formation ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Rake Angle ◽  
Critical Transition ◽  
Cutting Depth ◽  
Edge Defect ◽  
Edge Defects

In this paper, a finite element method was used to dynamically simulate the process of the edge defects formation during orthogonal cutting SiCp/Al composites. The influence of the cutting speed, cutting depth and rake angle of the PCD insert on the size of the edge defects have been investigated by using scanning electron. According to the simulated results, it can be provided that the cutting layer material has an effect on transfer stress and hinder the chip formation in the critical transition stage, and the critical transition point and distance are defined in this stage. The negative shear phenomenon is found when the chip transit to the edge defects in the flexure deformation stage, so the process of the chip formation is the basis of the edge defects formation. In addition, the relationship between the nucleation and propagation direction of the crack and the variation of the edge defect shape on the workpiece was investigated by theory, and it found that the negative shear angle formation is the primary cause of the edge defect formation. A mixed mode crack is found in the crack propagation stage. The sizes of edge defects were measured by the experiment and simulation, and the edge defect size decrease with the increasing of tool rake angle, while increase with increasing cutting depth and cutting speed.

Measuring fracture toughness from machining tests

2009 ◽  
Vol 223 (12) ◽  
pp. 2861-2869 ◽  
Author(s):  
Y Patel ◽  
B R K Blackman ◽  
J G Williams
Keyword(s):  
Fracture Toughness ◽  
Aluminium Alloy ◽  
Coefficient Of Friction ◽  
Metal Cutting ◽  
Orthogonal Cutting ◽  
Shear Plane ◽  
Rake Angle ◽  
Sufficient Information ◽  
The Coefficient Of Friction ◽  
Adhesion Toughness

An analysis of the forces involved in orthogonal cutting or machining is presented in which yielding on a shear plane is assumed. The fracture toughness Gc is included and it is observed that Gc may be determined by measuring the cutting and transverse forces together with the chip thickness for a range of cutting depths. This latter measurement enabled the shear plane angle ϕ to be determined experimentally. A simplified version of the analysis is also given in which ϕ is predicted by a cutting force minimization scheme. Neither scheme requires any details of the friction condition to be known since the transverse force is sufficient information for any type to be included in the analysis. A friction model including a coefficient of friction and an adhesion toughness is also utilized. Data for both polymer and metal cutting are taken from the literature and Gc is determined. In some datasets the tool rake angle α is also varied and the values of Gc and the yield stress σY are found to be independent of α. The force minimization method gives a good estimate of ϕ for most polymers. For metals (aluminium alloy, steel, and brass) the method worked well. For aluminium alloy Gc was independent of α and the predicted and measured ϕ values agreed. For steel and brass this was not so. Gc was mostly independent of α except at low values where high values of Gc were observed. A constant value of the coefficient of friction was observed for each α value but values for both the coefficient of friction and the adhesion toughness varied significantly with increasing rake angle.

Experiment Study of Adiabatic Shear Critical Conditions in Orthogonal Cutting of Fe-36Ni Invar Alloy

2011 ◽  
Vol 305 ◽  
pp. 198-201
Author(s):  
Guo He Li ◽  
Hou Jun Qi ◽  
Bing Yan
Keyword(s):  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Chip Morphology ◽  
Rake Angle ◽  
Adiabatic Shear ◽  
Invar Alloy ◽  
Critical Conditions ◽  
Cutting Depth ◽  
Deformation Coefficient ◽  
Cutting Experiments

Orthogonal cutting experiments of Fe-36Ni invar alloy are performed. The change of chip morphology with cutting conditions are investigated through metallurgical observation, and the critical cutting speed of adiabatic shear for Fe-36Ni invar alloy at different cutting depths and rake angles are given. In addition, the characteristic of chip deformation before the occurrence of adiabatic shear is also analyzed. The results show that the critical cutting speed decreases with the increase of cutting depth and hardness, but increases with the increase of rake angle. The deformation coefficient tends to a constant value with the increase of cutting speed.

scholarly journals Effect of Different Types of Block Copolymers on Morphology, Mechanical Properties, and Fracture Mechanisms of Bisphenol-F Based Epoxy System

2019 ◽  
Vol 3 (3) ◽  
pp. 68 ◽  
Author(s):  
Bajpai ◽  
Wetzel
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tensile Strength ◽  
Block Copolymers ◽  
Fracture Energy ◽  
Plastic Zone Size ◽  
Fracture Mechanisms ◽  
Epoxy System ◽  
Bisphenol F ◽  
Different Types

The effect of adding different types of soft block copolymer on the tensile properties, fracture mechanic properties, and thermo-mechanical properties of bisphenol F based epoxy resin were studied. Two different self-assembling block copolymers, (a) constituting of a center block of poly (butyl acrylate) and two side blocks of poly (methyl) methacrylate-co-polar co-monomer (BCP 1) and (b) poly(ethylene oxide)-b-poly(butylene oxide) (PEO-PBO) diblock copolymer (BCP 2), were used with an epoxy-hardener system. The maximum fracture toughness and fracture energy were measured as KIc = 2.75 MPa·m1/2 and GIc = 2.37 kJ/m2 for the 10 wt % of BCP 1 modified system, which were 366% and 2270% higher in comparison to reference epoxy system, and a 63% reduction in tensile strength was also observed. Similarly, for BCP2 modified systems, the maximum value of KIc = 1.65 MPa·m1/2 and GIc = 1.10 kJ/m2 was obtained for epoxy modified with 12 wt % of BCP2 and a reduction of 32% in tensile strength. The fracture toughness and fracture energy were co-related to the plastic zone size for all the modified systems. Finally, the analysis of the fracture surfaces revealed the toughening micro-mechanisms of the nanocomposites.

Finite Element Simulation of Cutting Forces in Orthogonal Machining of Titanium Alloy Ti-6Al-4V

2014 ◽  
Vol 474 ◽  
pp. 192-199 ◽  
Author(s):  
Ladislav Kandráč ◽  
Ildikó Maňková ◽  
Marek Vrabel' ◽  
Jozef Beňo
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cutting Forces ◽  
Orthogonal Cutting ◽  
Experimental Studies ◽  
Cutting Speed ◽  
Rake Angle ◽  
Simulation Software ◽  
Tool Geometry ◽  
Element Method

In this paper, a Lagrangian finite element-based machining model is applied in the simulation of cutting forces in two-dimensional orthogonal cutting of titanium Ti-6Al-4V alloy. The simulations were conducted using 2D Finite Element Method (FEM) machining simulation software. In addition, the cutting experiments were carried out under the different cutting speed, feed and tool geometry (rake angle, clearance angle and cutting edge radius). The effect of cutting speed, feed and tool geometry on cutting force were investigated. The results obtained from the finite element method (FEM) and experimental studies were compared.

Experimental Study and Theory Prediction on Adiabatic Shear Critical Conditions of Fe-36Ni Invar Alloy

2011 ◽  
Vol 188 ◽  
pp. 110-115
Author(s):  
Guo He Li ◽  
Min Jie Wang
Keyword(s):  
Experimental Study ◽  
Chip Formation ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Rake Angle ◽  
Adiabatic Shear ◽  
Invar Alloy ◽  
Critical Conditions ◽  
Cutting Depth ◽  
Cutting Experiments

Orthogonal cutting experiments of Fe-36Ni invar alloy are performed to investigate the influence of cutting conditons on adiabtic shear, which occurs in the process of chip formation of many materials. It is found that the cutting speed, cutting depth and rake angle all have influence on adiabatic shear and there is a critical cutting speed at which the adiabatic shear appears. By metallurgical observation, the critical cutting speed under different cutting depth and rake angles are given. A model based on linear pertubation analysis is used to predict the adiabatic shear critical ctting conditions of Fe-36Ni invar alloy. The comparison of prediction results and that of expriments shows that this prediction model is available.

Reserch on Cutting Depth Effect in Cutting Process

2011 ◽  
Vol 128-129 ◽  
pp. 251-254
Author(s):  
Zhao Wei Dong ◽  
Xiao Hang Wan ◽  
Shu Jun Li ◽  
Sheng Yong Liu
Keyword(s):  
Residual Stress ◽  
Cutting Forces ◽  
Orthogonal Cutting ◽  
Fem Analysis ◽  
Work Piece ◽  
Cutting Depth ◽  
Depth Effect ◽  
Chip Breaking ◽  
The Status ◽  
Cutting Model

In the cutting procedure, the cutting depth influences cutting forces, chip breaking, chip shaping, and the distribution status of residual stress. The two-dimension heat-mechanic coupling orthogonal cutting model is established with the FEM analysis software by use of the Lagrange quality point coordinate system description method in this paper. This paper simulates a typical work-piece chip breaking process with different cutting depth, which gets the cutting forces curves and the total status of residual stress distribution and the status.

An Experimental Study of Orthogonal Cutting of SiCp/Al Composites: Cutting Forces Analysis

2012 ◽  
Vol 500 ◽  
pp. 230-235
Author(s):  
Shu Tao Huang ◽  
Li Zhou ◽  
Jin Lei Wang
Keyword(s):  
Cutting Force ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Rake Angle ◽  
Mechanical And Thermal Properties ◽  
Cutting Depth ◽  
Metal Parts ◽  
Orthogonal Machining ◽  
Rapid Tool

Due to the superior mechanical and thermal properties of SiCp/Al composites, their poor machinability has been the main deterrent to their substitution for metal parts. Machining of SiCp/Al composites has been considerably difficult because the extremely abrasive nature of SiC reinforcements causes rapid tool wear. In this paper, an experiment was carried out to investigate the influence of the cutting speed, cutting depth and tool rake angle on cutting force during orthogonal machining of SiCp/Al composites. The results indicate that the cutting depth is one of the main cutting parameters that affect the cutting force, while the cutting speed and tool rake angle have no significant effects on the cutting force.

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