Numerical Predictions of Fiber Orientation for Injection Molded Rectangle Plate and Tensile Bar with Experimental Validations

2018 ◽  
Vol 33 (1) ◽  
pp. 96-105 ◽  
Author(s):  
H.-C. Tseng ◽  
R. Y. Chang ◽  
C.-H. Hsu
Keyword(s):  
Fiber Orientation ◽  
Numerical Predictions ◽  
Injection Molded ◽  
Experimental Validations

Predictions of fiber concentration in injection molding simulation of fiber-reinforced composites

2017 ◽  
Vol 31 (11) ◽  
pp. 1529-1544 ◽  
Author(s):  
Huan-Chang Tseng ◽  
Rong-Yeu Chang ◽  
Chia-Hsiang Hsu
Keyword(s):  
Injection Molding ◽  
Fiber Orientation ◽  
Short Fiber ◽  
Core Structure ◽  
Particle Migration ◽  
Migration Behavior ◽  
Fiber Concentration ◽  
Numerical Predictions ◽  
Injection Molding Simulation ◽  
Injection Molded

The microstructures of injection-molded short fiber composites, involving fiber orientation and fiber concentration, strikingly influence flow behaviors and mechanical properties. Through the use of certain commercial software, reported numerical predictions of fiber orientation for the shell–core structure have been obtained to date. However, no work has been done on fiber concentration prediction available in processing simulations. In the theoretical field of suspension rheology, the suspension balance (SB) model has proven successful in capturing particle migration behavior under the simple Couette shear flow of “spherical” particle suspension, hence the attempt to verify the SB model applied in the “like-rod” suspensions. To predict flow-induced variations of fiber concentration, the SB model is implemented in 3-D-injection molding simulation with more general flows. It is remarkable for the shell–core structure is explored to reflect the relationship between fiber orientation and fiber concentration.

Weld Lining Strength of Injection Molded Jute/PLA and Jute/PP

2012 ◽  
Author(s):  
Cuntao Wang ◽  
Yuqiu Yang ◽  
Masuo Urakami ◽  
Hiroyuki Hamada
Keyword(s):  
Fiber Orientation ◽  
Line Strength ◽  
Weld Line ◽  
Fiber Bundles ◽  
Interfacial Property ◽  
Fiber Distribution ◽  
Molded Parts ◽  
Injection Molded ◽  
Hybrid Mixtures ◽  
Better Than

Weld lines are formed inevitably when two separate melt fronts rejoin during injection molding. It has been reported that weld lines greatly weaken the strength of injection-molded parts. Therefore, in this paper the weld property of injection molded jute /PLA and jute/PP dumbbell shape specimen with weld line was investigated by changing pellets materials. In the study pultrusion technique was adopted to fabricate jute/PLA and jute/PP long fiber pellets (LFT) and it was found that fiber bundles in LFT specimens were not separated and dispersed well. As a result, in this paper re-compound pellets of LFT, i.e. RP was made. Then LFT, RP, and hybrid mixtures with the hybrid ratios of LFT50:RP50 were used to mold dumbbell shape specimens with or without weld line. In particular, the influence of different pellets on weld line strength of injection molded jute/PLA and jute/PP dumbbell shape specimens with weld line was discussed based on tensile test and SEM observation. It was found that tensile strength of RP specimens was higher than that of LFT both for jute/PLA and jute/PP, because fiber distribution and interfacial property of RP was much better than that of LFT. Weld line strength of RP was improved than that of LFT both for jute/PLA and jute/PP. RP of jute/PLA was more effective to improve the weld property than that of jute/PP. Weld line strength of jute/PP LFT increased as holding pressure increased from 44 to 88 MPa and decreased at 132 MPa holding pressure. It depends on the co-effect of fiber orientation and voids content.

Thermal Anisotropy in Injection Molded Polymer Composite Fins

2010 ◽  
Author(s):  
Avram Bar-Cohen ◽  
Patrick Luckow ◽  
Juan G. Cevallos ◽  
S. K. Gupta
Keyword(s):  
Heat Transfer ◽  
Polymer Composite ◽  
Thermal Characteristics ◽  
Axial Direction ◽  
Transfer Coefficients ◽  
Thermal Anisotropy ◽  
Modeling Methodology ◽  
Numerical Predictions ◽  
Injection Molded ◽  
Global And Local

An integrated molding-heat transfer modeling methodology is used to study the thermal characteristics of polymer composite fins subjected to convective heat transfer coefficients. Numerical predictions of the fiber orientation in a representative, injection-molded plate fin, based on the Folgar-Tucker model, are used, via the classic Nielsen model, to determine the anisotropic variation of thermal conductivity in the fin. Thermal simulations are then performed to determine the effect of both global and local thermal anisotropy on the temperature distribution and heat transfer rate of the anisotropic fin. It is also shown that the harmonic mean conductivity, in the axial direction, can be used to represent the heat loss of an anisotropic fin to better than 10% accuracy.

Creep Modeling for Injection-Molded Long-Fiber Thermoplastics

2008 ◽  
Author(s):  
Ba Nghiep Nguyen ◽  
Vlastimil Kunc ◽  
Satish K. Bapanapalli
Keyword(s):  
Fiber Orientation ◽  
Fiber Length ◽  
Creep Model ◽  
Elastic Fibers ◽  
Injection Molding Process ◽  
Creep Response ◽  
Equivalent Inclusion Method ◽  
Long Fiber Thermoplastics ◽  
Orientation Distributions ◽  
Injection Molded

This paper proposes a model to predict the creep response of injection-molded long-fiber thermoplastics (LFTs). The model accounts for elastic fibers embedded in a thermoplastic resin that exhibits the nonlinear viscoelastic behavior described by the Schapery’s model. It also accounts for fiber length and orientation distributions in the composite formed by the injection-molding process. Fiber length and orientation distributions were measured and used in the analysis that applies the Eshelby’s equivalent inclusion method, the Mori-Tanaka assumption (termed the Eshelby-Mori-Tanaka approach) and the fiber orientation averaging technique to compute the overall strain increment resulting from an overall constant applied stress during a given time increment. The creep model for LFTs has been implemented in the ABAQUS finite element code via user-subroutines and has been validated against the experimental creep data obtained for long-glass-fiber/polypropylene specimens. The effects of fiber orientation and length distributions on the composite creep response are determined and discussed.

Fiber Orientation in Injection-Compression Molded Short-Fiber-Reinforced Polypropylene Parts

2009 ◽  
Author(s):  
Han-Xiong Huang ◽  
Can Yang ◽  
Kun Li
Keyword(s):  
Fiber Orientation ◽  
Flow Direction ◽  
Processing Parameters ◽  
Short Fiber ◽  
Fiber Reinforced ◽  
Compression Force ◽  
Time Compression ◽  
Compression Time ◽  
Molded Parts ◽  
Injection Molded

Four processing parameters, including compression force, compression time, compression distance, and delay time, were investigated in terms of their effects on the fiber orientation in injection-compression molded (ICM) short-fiber-reinforced polypropylene parts. The results reveal that the fiber orientation pattern in ICM parts is different from that in conventional injection molded parts. Compression force plays an important role in determining the fiber orientation, whereas the effect of compression time can be neglected. Moreover, the fiber orientation changes obviously in the width direction, with most fibers arranging orderly in the flow direction at positions near the mold cavity wall.

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