Fracture toughness of polymers in shear mode

Kwon, Hyock-Ju; Jar, P.‐Y. Ben

doi:10.1016/j.polymer.2005.10.074

Cited by 22 publications

(27 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This method provides an effective means of dealing with gross ductility that can occur in the plane stress fracture state. It has been widely employed to measure the fracture toughness of ductile polymers [25][26][27], and short fibre reinforced polymers [28]. However, this theory has not been applied to measure the fracture toughness of continuous fibre reinforced composites.…”

Section: Introductionmentioning

confidence: 99%

Modelling the nonlinear behaviour and fracture process of AS4/PEKK thermoplastic composite under shear loading

Tan

Falzon

2016

Composites Science and Technology

View full text Add to dashboard Cite

The accurate determination of non-linear shear behaviour and fracture toughness of continuous carbonfibre/polymer composites remains a considerable challenge. These measurements are often necessary to generate material parameters for advanced computational damage models. In particular, there is a dearth of detailed shear fracture toughness characterisation for thermoplastic composites which are increasingly generating renewed interest within the aerospace and automotive sectors. In this work, carbon fibre (AS4)/ thermoplastic Polyetherketoneketone (PEKK) composite V-notched cross-ply specimens were manufactured to investigate their non-linear response under pure shear loading. Both monotonic and cyclic loading were applied to study the shear modulus degradation and progressive failure. For the first time in the reported literature, we use the essential work of fracture approach to measure the shear fracture toughness of continuous fibre reinforced composite laminates.Excellent geometric similarity in the load-displacement curves was observed for ligament-scaled specimens. The laminate fracture toughness was determined by linear regression, of the specific work of fracture values, to zero ligament thickness, and verified with computational models. The matrix intralaminar fracture toughness (ply level fracture toughness), associated with shear loading was determined by the area method. This paper also details the numerical implementation of a new three-dimensional phenomenological model for carbon fibre thermoplastic composites using the measured values, which is able to accurately represent the full non-linear mechanical 2 response and fracture process. The constitutive model includes a new non-linear shear profile, shear modulus degradation and load reversal. It is combined with a smeared crack model for representing ply-level damage initiation and propagation. The model is shown to accurately predict the constitutive response in terms of permanent plastic strain, degraded modulus as well as load reversal. Predictions are also shown to compare favourably with the evolution of damage leading to final fracture.

show abstract

Section: Introductionmentioning

confidence: 99%

Modelling the nonlinear behaviour and fracture process of AS4/PEKK thermoplastic composite under shear loading

Tan

Falzon

2016

Composites Science and Technology

View full text Add to dashboard Cite

show abstract

“…For determination of shear fracture toughness of HDPE, use of EWF was adopted earlier by Kwon and Jar [8,9] with a standard Iosipescu test and they proposed a SWF expression as in Eq 2. There are two shape factors, , one depending on ligament length and another on thickness.…”

Section: Finite Element Simulation and Essential Work Of Fracturementioning

confidence: 99%

“…This makes the shear testing difficult by contamination of normal loading prior to failure. Kwon and Jar used side grooved double edge notched (DEN) specimen to guide Iosipescu test of HDPE toward pure shear [8,9].…”

Section: Introductionmentioning

confidence: 99%

Study of Ligament Length Effect on Mode Mix of a Modified In-Plane Shear Test Specimen

Islam

Kao-Walter

Yang

2016

Matls. Perf. Charact.

View full text Add to dashboard Cite

Shear fracture toughness is an important material behavior that needs to be determined and considered in many industrial fields. At the same time, shear testing is one of the complex material testing areas where available methods are few, often need special arrangements and most of the methods do not strictly satisfy the definition of pure shear. In this study, a modified shear test specimen was proposed to measure the shear fracture toughness by uniaxial loading in a tensile testing machine. High Density Polyethylene (HDPE) was used as test material for the experiments. The specimen was created in order to suit the most common used tensile test machine. The specimen was then optimized by using Finite Element Analysis (FEA) to find the geometry and the size of the pre-notch to avoid the mixed mode loading and minimize effects of normal stresses. For the specimen in discussion, an upper and lower limit of usable ligament length can be found. Finally, a method for determining the fracture toughness was discussed according to the essential work of fracture.

show abstract

“…For double-edge-notched specimens subjected to mode II loading, such as that in Iosipescu test, expression for the specific work of fracture, w I I f , has been suggested to be (Kwon and Jar 2005):…”

Section: Essential Work Of Fracture (Ewf)mentioning

confidence: 99%

“…A new test methodology was reported in our previous paper (Kwon and Jar 2005) for measuring essential work of fracture (EWF) of polymers in shear mode (mode II). The study concludes that side grooves along the ligament of double-edge-notched (DEN) specimens facilitate the alignment of the shear band in the loading direction, thus encouraging specimen fracture in mode II.…”

Section: Introductionmentioning

confidence: 99%

Toughness of high-density polyethylene in shear fracture

Kwon

Jar

2007

Int J Fract

View full text Add to dashboard Cite

This paper evaluates the validity of a new test methodology for measuring shear fracture toughness (mode II) of high density polyethylene (HDPE). The methodology adopts Iosipescu test for the shear loading, and determines the toughness based on the essential work of fracture (EWF) concept. The results show that even under the Iosipescu loading, tensile deformation (mode I) is still involved in the fracture process, possibly due to the significant work hardening that HDPE develops during the plastic deformation. The study found that the mode II fracture toughness can be determined through data analysis using double linear regression, i.e., by extrapolating specific work of fracture to zero ligament length and zero ligament thickness. The paper demonstrates that the new test methodology can be used to evaluate mode II fracture toughness of ductile polymers like HDPE in which significant work-hardening may be involved in the fracture process. The paper also provides quantitative comparison of the fracture toughness for HDPE in mode II with its mode I counterpart.

show abstract

Fracture toughness of polymers in shear mode

Cited by 22 publications

References 34 publications

Modelling the nonlinear behaviour and fracture process of AS4/PEKK thermoplastic composite under shear loading

Modelling the nonlinear behaviour and fracture process of AS4/PEKK thermoplastic composite under shear loading

Study of Ligament Length Effect on Mode Mix of a Modified In-Plane Shear Test Specimen

Toughness of high-density polyethylene in shear fracture

Contact Info

Product

Resources

About