The Effects of Hydrostatic Pressure on the Mechanical Behavior of Polymers

Pae, K. D.; Bhateja, S. K.

doi:10.1080/15321797508068145

Cited by 88 publications

(27 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In their survey of materials, they found that while all polymers exhibit pressure dependent properties, some features are material specific, and some are observed across all polymers, namely that increasing hydrostatic pressure results in increased modulus and yield stress, sometimes by as much as 50-100 %. Increasing pressure in materials where the glass transition is below room temperature was found to shift the transition to room temperature, for example in LDPE [22], similar to time-temperature superposition. Due to the differences in underlying deformation mechanisms, the ductility and post yield behavior in polymers varies by material [22].…”

Section: Pressure Effects In Polymersmentioning

confidence: 85%

“…Increasing pressure in materials where the glass transition is below room temperature was found to shift the transition to room temperature, for example in LDPE [22], similar to time-temperature superposition. Due to the differences in underlying deformation mechanisms, the ductility and post yield behavior in polymers varies by material [22].…”

Section: Pressure Effects In Polymersmentioning

confidence: 85%

“…The first study where a polymer was loaded under hydrostatic pressure was conducted by Bridgman in 1953 [191]. In 1975, Pae and Bhateja [22] wrote a review of the effects of hydrostatic pressure on the mechanical behavior of polymers, including specific properties of the polymers that had been characterized to date. In their survey of materials, they found that while all polymers exhibit pressure dependent properties, some features are material specific, and some are observed across all polymers, namely that increasing hydrostatic pressure results in increased modulus and yield stress, sometimes by as much as 50-100 %.…”

Section: Pressure Effects In Polymersmentioning

confidence: 99%

“…Alternatively, the increased strength in rubbery amorphous polymers is accounted for by the change in molecular mobility during the glass transition, or a-transition. The key feature is that a transition, which is typically observed below room temperature, is observed at room temperature for high strain rates, as the transition temperature increases with increasing strain rate [5,15,16,19,20] The effect of confining pressure has not been well studied in polymers, and there are limited reports in the literature [21,22]. Quasi-static experiments have shown that increased hydrostatic confining pressure results in linearly-dependent, increased yield strength and decreased strain to failure in tension [22].…”

Section: Introductionmentioning

confidence: 99%

“…The key feature is that a transition, which is typically observed below room temperature, is observed at room temperature for high strain rates, as the transition temperature increases with increasing strain rate [5,15,16,19,20] The effect of confining pressure has not been well studied in polymers, and there are limited reports in the literature [21,22]. Quasi-static experiments have shown that increased hydrostatic confining pressure results in linearly-dependent, increased yield strength and decreased strain to failure in tension [22]. This pressure dependence manifests itself in differences between the tensile and compressive yield stresses, which can aid in the determination of pressure dependence without a requirement for the complex loading apparatus required for applying hydrostatic pressure [18,20,23].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

High Strain Rate Mechanics of Polymers: A Review

Siviour

Jordan

2016

J. dynamic behavior mater.

275

121

View full text Add to dashboard Cite

The mechanical properties of polymers are becoming increasingly important as they are used in structural applications, both on their own and as matrix materials for composites. It has long been known that these mechanical properties are dependent on strain rate, temperature, and pressure. In this paper, the methods for dynamic loading of polymers will be briefly reviewed. The high strain rate mechanical properties of several classes of polymers, i.e. glassy and rubbery amorphous polymers and semi-crystalline polymers will be reviewed. Additionally, time-temperature superposition for rate dependent large strain properties and pressure dependence in polymers will be discussed. Constitutive modeling and shock properties of polymers will not be discussed in this review.

show abstract

Section: Pressure Effects In Polymersmentioning

confidence: 85%

Section: Pressure Effects In Polymersmentioning

confidence: 85%

Section: Pressure Effects In Polymersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

High Strain Rate Mechanics of Polymers: A Review

Siviour

Jordan

2016

J. dynamic behavior mater.

275

121

View full text Add to dashboard Cite

show abstract

Yield and Crazing in Polymers

O’Connell

McKenna

2004

Encyclopedia of Polymer Science and Technology

View full text Add to dashboard Cite

The present article discusses yield and crazing in polymeric materials. After introducing the definitions of stress and strain states, we present a brief summary of the general stress–strain responses for polymers under uniaxial tensile and compressive loading. We introduce the various regimes of behavior, from almost linear elastic through the nonlinear response to rubber‐like behavior. We also include the concepts of necking and cold drawing and the Considère construction for determining whether a material will undergo either of these processes. The history of the development of yield criteria and models is then examined in some details. Yield criteria, which may be considered as macroscopic criteria relating the applied stress state to a critical value for yielding, are first discussed and the modifications for pressure dependence introduced. These criteria, while useful from an engineering point of view in that they offer a method to estimate the likelihood of failure for a given loading situation, provide no insight into the microscopic or molecular mechanisms that give rise to yield. Early theories of yield (eg adiabatic heating and strain induced dilatation), though now considered incorrect, are mentioned in their historical context. A number of models are then presented which consider yield as an activated process. In these models, resistance to yielding is considered as being due to inter‐ and/or intramolecular forces. Application of stress (or the associated strain) affects the energy landscape of the material such that the energy barrier for this resistance is reduced and yield can occur. More complex models are then presented which address not only the yield of the material but the subsequent strain‐softening and strain‐hardening events that are observed. We conclude the section on yield by some brief, general observations on dislocation plasticity, the ultimate shear strength, dilatometry and calorimetry, computer modeling, and finally some discussion of yield in semi‐crystalline materials. The second section of the current chapter discusses the phenomenon of crazing. Crazing is a microscopically localized phenomenon, which involves a large degree of localized plastic deformation. Yet, crazing is generally the precursor to macroscopically brittle failure at low craze densities. An overview of craze morphology is first given to familiarize the reader with the main structural features of crazes. The development of a craze can be conveniently subdivided into three stages—initiation, growth, and failure—and each stage is examined separately. As with the yield section, craze initiation is examined in an historical context and the development of theories considering, variously, a critical cavitation stress, a critical strain, or the presence of inherent microvoids which can grow under the applied local stress or strain are discussed. There is general consensus on the mechanisms for craze growth. Craze tip advance is thought to occur by the Taylor meniscus instability mechanism, while craze thickening is due to the drawing in of material from the bulk–fibril interface. Both these mechanisms are presented and the dependence on, for example, molecular weight and cross‐link density discussed. Craze failure is examined in terms of either fibril failure or failure at the bulk–fibril interface. The section is completed by considering other factors for craze formation and failure (effect of cross‐tie fibrils, environmental‐stress cracking, and fatigue failure).

show abstract