A Uniform Pure Shear Testing Specimen for Adhesive Characterization

No uniﬁed stress-based criterion exists, in the literature, for predicting the rupture of hyperelastic materials subjected to mutiaxial loading paths. This paper aims to establish a generalized rupture criterion under plane stress loading for elastomers. First, the experimental set up, at breaking, including various loading modes, is briefly described and commented. It consists of uniaxial tests, biaxial tests and pure shear tests, performed on different rubbers. The used vulcanizate and thermoplastic rubber materials are a Natural Rubber (NR), a Styrene Butadiene Rubber (SBR), a Polyurethane (PU) and a Thermoplastic elastomer (TPE). Then, we have investigated a new theoretical approach, based upon the principal stresses, to establish a failure criterion under quasi-static loadings. Thus, we have proposed a new analytical model expressed as a function of octahedral stresses. Quite good agreement is highlighted when comparing the ultimate stresses, at break, between the experimental data and the prediction of the proposed criteria using our rubber-like materials.

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A new method for ultrasonic fatigue testing of equibiaxial and pure shear cruciform specimens

International Journal of Fatigue ◽

10.1016/j.ijfatigue.2021.106423 ◽

2021 ◽

pp. 106423

Author(s):

Pedro R. da Costa ◽

Luís Reis ◽

Diogo Montalvão ◽

Manuel Freitas

Keyword(s):

Fatigue Testing ◽

Pure Shear ◽

New Method ◽

Ultrasonic Fatigue

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Multiaxial Fatigue of 16MnR Steel

Journal of Pressure Vessel Technology ◽

10.1115/1.3008041 ◽

2008 ◽

Vol 131 (2) ◽

Cited By ~ 29

Author(s):

Zengliang Gao ◽

Tianwen Zhao ◽

Xiaogui Wang ◽

Yanyao Jiang

Keyword(s):

Pure Shear ◽

Ambient Air ◽

Shear Loading ◽

Multiaxial Fatigue ◽

Experimental Results ◽

Pressure Vessel Steel ◽

Critical Plane ◽

Cracking Behavior ◽

Vessel Steel ◽

Axial Torsion

Uniaxial, torsion, and axial-torsion fatigue experiments were conducted on a pressure vessel steel, 16MnR, in ambient air. The uniaxial experiments were conducted using solid cylindrical specimens. Axial-torsion experiments employed thin-walled tubular specimens subjected to proportional and nonproportional loading. The true fracture stress and strain were obtained by testing solid shafts under monotonic torsion. Experimental results reveal that the material under investigation does not display significant nonproportional hardening. The material was found to display shear cracking under pure shear loading but tensile cracking under tension-compression loading. Two critical plane multiaxial fatigue criteria, namely, the Fatemi–Socie criterion and the Jiang criterion, were evaluated based on the experimental results. The Fatemi–Socie criterion combines the maximum shear strain amplitude with a consideration of the normal stress on the critical plane. The Jiang criterion makes use of the plastic strain energy on a material plane as the major contributor to the fatigue damage. Both criteria were found to correlate well with the experiments in terms of fatigue life. The predicted cracking directions by the criteria were less satisfactory when comparing with the experimentally observed cracking behavior under different loading conditions.

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Effect of the Process Parameters on the Adhesive Strength of Dissimilar Polymers Obtained by Multicomponent Injection Molding

Polymers ◽

10.3390/polym13071039 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1039 ◽

Cited By ~ 1

Author(s):

Luciano Pisanu ◽

Leonardo Costa Santiago ◽

Josiane Dantas Viana Barbosa ◽

Valter Estevão Beal ◽

Marcio Luis Ferreira Nascimento

Keyword(s):

Adhesive Strength ◽

Natural Fiber ◽

Fiber Composite ◽

Pure Shear ◽

Central Area ◽

Dissimilar Materials ◽

Type I ◽

Coconut Fiber ◽

Adhesive Properties ◽

Experimental Conditions

The growing demand in the consumer market for products with sustainable technologies has motivated new applications using overmolded natural fiber composites. Therefore, studies have been conducted mainly to understand the adhesive properties of overmolded parts. In the present study, a polypropylene (PP) composite with 30% coconut fibers without additives was developed with the aid of a corotating twin screw extruder. Subsequently, a multicomponent injection mold was developed based on the geometry of the ISO 527 type I specimen, in which samples overmolded with PP and PP–coconut-fiber composite, with the overlap in the central area, were obtained to evaluate the adhesive strength of dissimilar materials. The objective of this study was to evaluate the bond between PP and PP–coconut-fiber composite under different processing conditions using an adhesive strength testing device to perform a pure shear analysis. The experimental conditions followed a statistical design considering four factors in two levels and a significance level of 5%. The results indicated that adhesive strength increased significantly as the overlap area increased. It was observed that temperature and injection flow rate were the factors that most contributed to strengthening the bonds of dissimilar materials.

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