Residual stress build-up in thermoset films cured below their ultimate glass transition temperature

Lange, Jakob; Toll, Staffan; Månson, Jan‐Anders E.; Hult, Anders

doi:10.1016/s0032-3861(96)00584-8

Cited by 78 publications

(61 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In fact, its state is rubbery and almost liquid so the capability to interact with the fibres by transferring stresses is negligible. These results agree with most of the published work on residual stresses in which thermal cooling was evaluated as the main source of residual stress in polymer composites [33,34].…”

Section: Residual Stresssupporting

confidence: 91%

Finite element investigations on the microstructure of fibre-reinforced composites

Maligno¹,

Warrior²,

Long³

2008

Express Polym. Lett.

View full text Add to dashboard Cite

Abstract. The effect of residual stress due to the curing process on damage evolution in unidirectional (UD) fibre-reinforced polymer-matrix composites under longitudinal and transverse loading has been investigated using a three-dimensional micromechanical representative volume element (RVE) model with a hexagonal packing geometry and the finite element method. Residual stress has been determined by considering two contributions: volume shrinkage of matrix resin from the crosslink polymerization during isothermal curing and thermal contraction of both resin and fibre as a result of cooling from the curing temperature to room temperature. To examine the effect of residual stress on failure, a study based on different failure criteria and a stiffness degradation technique has been used for damage analysis of the RVE subjected to mechanical loading after curing for a range of fibre volume fractions. Predicted damage initiation and evolution are clearly influenced by the presence of residual stress.

show abstract

Section: Residual Stresssupporting

confidence: 91%

Finite element investigations on the microstructure of fibre-reinforced composites

Maligno¹,

Warrior²,

Long³

2008

Express Polym. Lett.

View full text Add to dashboard Cite

show abstract

“…It is important to note that the chemical shrinkage measured by the proposed technique is not a total chemical shrinkage but a portion of the total chemical shrinkage that accumulates after the gelation point [22,23]. After the epoxy was cured completely, the FBG/epoxy assembly was subjected to a temperature excursion at an interval of 10°C and the BW was monitored as a function of temperature.…”

Section: Resultsmentioning

confidence: 99%

Integrated Measurement Technique for Curing Process-Dependent Mechanical Properties of Polymeric Materials Using Fiber Bragg Grating

et al. 2007

View full text Add to dashboard Cite

We propose an integrated technique to measure critical mechanical properties of polymeric materials. The method is based on a fiber Bragg grating (FBG) sensor. A polymer of interest is cured around a glass FBG and the Bragg wavelength (BW) shift is measured and documented while polymerization progresses at the curing temperature. After complete polymerization, the BW shift is monitored continuously as the temperature of the cured polymer changes. The desired material properties are then found inversely from the relationship between the Bragg wavelength shift and the deformation of the polymer caused by the changes in the material properties.

show abstract

“…[32][33][34] The build-up of residual stresses in thermoset films was investigated for resins with different crosslink densities by Lange. [35][36][37] The author used time-and temperature-dependant mechanical properties of the resins, such as shear modulus, relaxation modulus and film thickness during curing as well as bi-layer beam bending technique for stress prediction. Furthermore, he estimated contributions from the different parts of the cure progress on the overall residual stresses.…”

Section: Full Papermentioning

confidence: 99%

Influence of Cure Regime on the Strain Development in an Epoxy Resin as Monitored by a Fiber Bragg Grating Sensor

Harsch

Karger‐Kocsis

Herzog

2007

Macro Materials & Eng

View full text Add to dashboard Cite

In this paper, the effects of different cure regimes on the strain development in an anhydride‐cured epoxy resin were investigated by fiber optical measurements. The course of the strain signal was detected by an embedded fiber Bragg grating sensor in the unconstrainedly curing epoxy. The build‐up of strain was detected for various cure regimes differing in the dwelling times of the first isothermal step, heating rates to the cure temperature, and final curing temperatures, respectively. Characteristic points (gelation, vitrification) of the cure regimes were identified by conversion‐ and Tg‐determinations via DSC and assigned to changes of the FBG signal. The fiber Bragg sensing technique allowed us to find those variables of the cure regimes which mostly affect the strain development and thus, the level of the residual strain. It was established that the dwelling time and heating rate to the cure temperature influence markedly the residual strain whereas the cure temperature affects this value to a lesser extent for the selected cure regimes. So, the above parameters should be selected properly for an optimum cure regime characterized by the build‐up of a minimum residual strain.magnified image

show abstract

Residual stress build-up in thermoset films cured below their ultimate glass transition temperature

Cited by 78 publications

References 8 publications

Finite element investigations on the microstructure of fibre-reinforced composites

Finite element investigations on the microstructure of fibre-reinforced composites

Integrated Measurement Technique for Curing Process-Dependent Mechanical Properties of Polymeric Materials Using Fiber Bragg Grating

Influence of Cure Regime on the Strain Development in an Epoxy Resin as Monitored by a Fiber Bragg Grating Sensor

Contact Info

Product

Resources

About