FE Analysis of the Influence of Fiber Orientation to Shearing and Wrinkling of Fiber Reinforced Thermoplastic Parts

2017 ◽  
Vol 742 ◽  
pp. 732-739 ◽  
Author(s):  
Bernd Engel ◽  
Jasmin Graef
Keyword(s):  
Shear Stress ◽  
Fiber Orientation ◽  
Shear Angle ◽  
Fe Analysis ◽  
Angular Misalignment ◽  
Loading Direction ◽  
Cutting Machine ◽  
Bias Extension ◽  
Reinforced Thermoplastics ◽  
Fiber Misalignment

This work presents the influence of deviations of fiber orientations of warp and weft yarns to the shear stress vs. shear angle behavior and the formation of wrinkles of fabric reinforced thermoplastics. FE results of bias-extension tests and the forming of a double dome part will be investigated with angular misalignment of the yarns and/or deviations of the blank to its loading direction. The prepregs or organic sheets may have imperfections like fiber misalignment or the prepregs of multilayered sheets are twisted against each other. Furthermore, there may be deviations to the idealized orientation caused by the operator or cutting machine for example.

scholarly journals Influence of the Initial Fiber Orientation on the Weld Strength in Welding of Glass Fiber Reinforced Thermoplastics

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Isabel Fiebig ◽  
Volker Schoeppner
Keyword(s):  
Glass Fiber ◽  
Fiber Orientation ◽  
Weld Strength ◽  
Fiber Reinforced ◽  
Hot Plate ◽  
Glass Fiber Reinforced ◽  
Vibration Welding ◽  
Reinforced Thermoplastics ◽  
Fiber Reinforced Thermoplastics ◽  
Initial Fiber

The welding factors are significantly lower in welding of fiber reinforced thermoplastics than in welding of unreinforced thermoplastics due to the fiber orientation in the weld. This paper presents results from investigations on the influence of the initial fiber orientation on the weld strength in hot plate and vibration welding for glass fiber reinforced polypropylene and polyamide 6. Injection molded specimens are compared to specimens with main initial fiber orientation being longitudinal and transverse to the joining direction. The results of CT analysis of the fiber orientation in the weld show the opportunity to achieve a higher weld strength by using specimens with fibers being initially oriented longitudinally to the joining direction. The influence of the initial fiber orientation in the parts to be welded on the weld strength in hot plate welding is more distinct than in vibration welding.

A New Model and Analysis of Orthogonal Machining With an Edge-Radiused Tool

1999 ◽  
Vol 122 (3) ◽  
pp. 384-390 ◽  
Author(s):  
Jairam Manjunathaiah ◽  
William J. Endres
Keyword(s):  
Shear Stress ◽  
Deformation Zone ◽  
Lower Boundary ◽  
Chip Thickness ◽  
Rake Angle ◽  
Shear Angle ◽  
Force Model ◽  
Uncut Chip Thickness ◽  
Edge Radius ◽  
Machining Force

A new machining process model that explicitly includes the effects of the edge hone is presented. A force balance is conducted on the lower boundary of the deformation zone leading to a machining force model. The machining force components are an explicit function of the edge radius and shear angle. An increase in edge radius leads to not only increased ploughing forces but also an increase in the chip formation forces due to an average rake angle effect. Previous attempts at assessing the ploughing components as the force intercept at zero uncut chip thickness, which attribute to the ploughing mechanism all the changes in forces that occur with changes in edge radius, are seen to be erroneous in view of this model. Calculation of shear stress on the lower boundary of the deformation zone using the new machining force model indicates that the apparent size effect when cutting with edge radiused tools is due to deformation below the tool (ploughing) and a larger chip formation component due to a lower shear angle. Increases in specific energy and shear stress are also due to shear strain and strain rate increases. A consistent material behavior model that does not vary with process input conditions like uncut chip thickness, rake angle and edge radius can be developed based on the new model. [S1087-1357(00)01302-2]

Sensitivity Study of Material Input Data on FE Forming Results for Wrinkling and Shearing of Fiber Reinforced Thermoplastic Parts

2019 ◽  
Vol 809 ◽  
pp. 500-505
Author(s):  
Bernd Engel ◽  
Jasmin Graef
Keyword(s):  
Input Data ◽  
Test Procedure ◽  
Material Model ◽  
Sensitivity Study ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Forming Process ◽  
Bias Extension ◽  
Reinforced Thermoplastics ◽  
Material Input

This work presents the analysis of the influence of several material input data to the FE results of the forming process of fiber reinforced thermoplastics within a sensitivity study. The *Fabric material model of Abaqus/Explicit is used for the description of the shear, tensile and compression behavior. It is a test-data based model. The bending behavior will be modeled with beam elements. The interaction between input data will be analyzed and its influence onto the FE forming results and FE analysis of material tests like bias-extension-test, compression and bending test with focus on interactions of input data and test procedure itself.

scholarly journals Uncertainty quantification of fiber orientation distribution measurements for long-fiber-reinforced thermoplastic composites

2017 ◽  
Vol 52 (13) ◽  
pp. 1781-1797 ◽  
Author(s):  
Bhisham N Sharma ◽  
Diwakar Naragani ◽  
Ba Nghiep Nguyen ◽  
Charles L Tucker ◽  
Michael D Sangid
Keyword(s):  
Cross Sections ◽  
Fiber Orientation ◽  
Surface Preparation ◽  
Orientation Distribution ◽  
Elastic Stiffness ◽  
Thermoplastic Composites ◽  
Fiber Reinforced ◽  
Fiber Orientation Distribution ◽  
Discontinuous Fiber ◽  
Reinforced Thermoplastics

We present a detailed methodology for experimental measurement of fiber orientation distribution in injection-molded discontinuous fiber composites using the method of ellipses on two-dimensional cross sections. Best practices to avoid biases occurring during surface preparation and optical imaging of carbon-fiber-reinforced thermoplastics are discussed. A marker-based watershed transform routine for efficient image segmentation and the separation of touching fiber ellipses is developed. The sensitivity of the averaged orientation tensor to the image sample size is studied for the case of long-fiber thermoplastics. A Mori–Tanaka implementation of the Eshelby model is then employed to quantify the sensitivity of elastic stiffness predictions to biases in the fiber orientation distribution measurements.

Prediction of Shear Angle in Oblique Cutting with Maximum Shear Stress and Minimum Energy Principles

1999 ◽  
Vol 121 (3) ◽  
pp. 399-407 ◽  
Author(s):  
E. Shamoto ◽  
Y. Altıntas
Keyword(s):  
Shear Stress ◽  
End Milling ◽  
Maximum Shear Stress ◽  
Minimum Energy ◽  
Shear Angle ◽  
Tool Geometry ◽  
Unknown Parameters ◽  
Flow Angle ◽  
Oblique Cutting ◽  
Cutting Mechanics

A new shear angle prediction theory is proposed for oblique cutting operations. Oblique cutting mechanics are described by two components of shear angle, two angles defining direction of resultant cutting force, and chip flow angle. The five unknown parameters describe the geometry of chip deformation, velocities and forces in oblique cutting. When combined with the material dependent shear stress and average chip—rake face friction coefficient, cutting forces in three Cartesian directions can be predicted. In this paper, the mechanics of oblique cutting are described by five expressions. Three of the expressions are derived from the kinematics of oblique cutting, and the remaining two are derived either by applying Maximum Shear Stress or Minimum Energy Principle on the process. Unlike the previous solutions, the proposed methods do not require any intuitive or empirical assumptions, but use only the material properties, tool geometry and the physical laws of deformation. The oblique cutting parameters and forces predicted by the proposed models agree well with the empirical and experimental results reported in the classical cutting literature. The proposed models are experimentally verified in predicting forces in helical end milling which has oblique cutting mechanics.

FE Analysis According to Hinge Condition of Micro Stage for Micro Cutting Machine

2004 ◽  
Vol 274-276 ◽  
pp. 343-348 ◽  
Author(s):  
Lee Ku Kwac ◽  
Jae Yeol Kim ◽  
Young Tae Cho
Keyword(s):  
Fe Analysis ◽  
Micro Cutting ◽  
Cutting Machine

FE Analysis of the Effect of Material Gradient on the Performance of a Functionally Graded Endodontic Prefabricated Parallel Post

2015 ◽  
Vol 752-753 ◽  
pp. 382-386 ◽  
Author(s):  
Wasim M.K. Helal ◽  
Dong Yan Shi ◽  
Zhi Kai Wang
Keyword(s):  
Shear Stress ◽  
Volume Fraction ◽  
Fe Analysis ◽  
Functionally Graded ◽  
Von Mises Stress ◽  
Sigmoid Function ◽  
Current Investigation ◽  
Element Analysis ◽  
The Difference ◽  
Von Mises

A study of the effect of material gradient on the performance of a functionally graded endodontic prefabricated parallel post (FGEPPP) is the main goal of the current study. Elastic modulus (E) of FGEPPP is considered to vary continuously from lower to upper surfaces. This variation is performed according the volume fraction. Based on a modified sigmoid function, the volume fraction will be defined in the present work. The primary goal of the current investigation is to analyze the difference between the performance of a homogeneous endodontic prefabricated parallel post (EPPP) and a FGEPPP through finite element analysis (FEA). In the current investigation, von Mises stress, and shear stress in FGEPPP case with a modified sigmoid function and in homogeneous EPPP case are carried out. After that, the effect of material gradient on the performance of an EPPP made of FGM was carried out through FEA in the current investigation. The simulation cases shown that, the maximum values of von Mises stress, and shear stress increase when increasing the value of “D”, and decrease when increasing the value of “w”.

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