摘要:

AbstractA study has been performed to determine the effect of the use of divinyl benzene(DVB) as a crosslinking agent in polymeric binders consisting of mixtures of styrene, acrylonitrile, and acrylamide, on the thermal stability and structure of polymer concretes(PC), containing sand and cement as an aggregate. The results indicate that the inclusion of DVB results in improvements in the thermal and mechanical stability. The improvements are attributed to three‐dimensional cross‐linking of the polymer due to the inclusion of DVB. The influence of the sand‐cement ratio on the structure of PC samples at 240°C are also dis

ISSN:0272-8397    

DOI:10.1002/pc.750020102

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractA study was conducted to evaluate mica‐poly(vinyl chloride) (PVC) composites. A highly filled PVC pipe formulation was selected as reference and a gradual replacement by mica of the calcium carbonate was conducted. The mica improved the fluxing time of the formulation by a factor of three without markedly affecting the equilibrium or maximum, torque. The results are optimized when there is a partial replacement of the calcium carbonate by mica, Orientation of the mica flakes enhances the young's modulus as well as the yield stress. A theoretical analysis shows a discrepancy from experimental results for high levels of mica. The rheological properties were studied with a Brabender plastograph and mechanical properties with a model TM‐SM Inst

ISSN:0272-8397    

DOI:10.1002/pc.750020103

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe complete sorption‐desorption equilibrium isotherms determined at 23° C indicate that glass fiber‐reinforced polymer (GRP) sheets weathered outdoors for 3 years absorb larger amounts of water vapor than the non‐weathered sheets. Sorption and desorption Kinetic results at 23° and two levels of relative pressure (p/p0= 0.80 andp/p0= 0.975) show that the weathered sheets absorb water vapor at considerably higher rates than the non‐weathered sheets. Larger amounts of sorbed water, and faster sorption and desorption will result in respectively greater magnitudes and higher rates of dimensional changes (swelling and shrinking). This accelerates the overall effects of environmentally exerted stress‐fatigue on the GR

ISSN:0272-8397    

DOI:10.1002/pc.750020104

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractStatic and fatigue properties of high glass content sheet molding compound (SMC) materials were studied at various temperatures. It was shown that the matrix plays an important role in both fatigue characteristics and failure mechanism of such randomly oriented short fiber composites. Specifically, vinyl ester matrix shows better fatigue properties and post‐fatigue performance than the polyester system considered her

ISSN:0272-8397    

DOI:10.1002/pc.750020105

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractCrack extension during fatigue loading is one of the primary causes of failure in engineering materials. While the fatigue crack resistance of homogeneous and even adhesive systems has received detailed study and characterization, relatively few and scattered results are available for fiber composites. One difficulty with obtaining such data for composites is their tendency to develop complex patterns of intra‐ and interlaminar damage which expand in a stable manner during fatigue. Such damage usually does not severely reduce the load carrying capacity of a structure but the complexity of the damage geometry has so far frustrated efforts to apply any unifying theories of growth. Measurement of the rate of macroscopic crack growth, through thickness crack extension, has been possible for certain composites and crack direction where the stable damage is constrained. These include cracks in 0°/90° laminates, woven fabric laminates, chopped strand mat laminates, sheet molding (SMC) materials, and short fiber reinforced thermoplastics. Macroscopic interlaminar cracks in continuous fiber systems have also received some recent attention. Fatigue crack growth in glass fiber composites for which most data are available, involves significant contributions from both static and cyclic load effects. A simple model for predicting fatigue crack growth rates from traditional S‐Ncurve and fracture toughness data has proven useful for certain well behaved systems. Limited study has also been made of the effects of moisture and salt water on the fatigue crack growth

ISSN:0272-8397    

DOI:10.1002/pc.750020106

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe mechanical behavior of epoxy, hydroxyethymetherylate and polystyrene composites containing various percentages of glass microspheres was investigated over a wide range of temperature. The effect of filler concentration of the ductile‐brittle transition and on the glass‐transition temperature of the composites is reported. The utility of various predictive models for the effect of filler concentration on mechanical properties is asses

ISSN:0272-8397    

DOI:10.1002/pc.750020107

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractAn experimental investigation was conducted to identify the failure mechanism and to understand damage propagation in compression‐loaded composite structures. The tests were conducted on several laminates of different ply orientation with thicknesses that ranged from 0.56 to 0.79 cm. The panels were damaged by 1.27‐cm‐diameter aluminum spheres propelled normal to the specimen surface at velocities ranging from 30 m/s to 140 m/s. Results indicate that there is significant internal laminate damage due to low‐velocity impact with no surface damage. The internal damage consists of delamination and intraply cracking. Three damage propagation modes were identified as causing specimen failure; delamination, axial load‐lateral deformation coupling, and local shea

ISSN:0272-8397    

DOI:10.1002/pc.750020108

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractCriteria have been developed for identifying, characterizing, and quantifying fracture modes in high‐modulus graphite‐fiber/resin unidirectional composites subjected to off‐axis tensile loading. Procedures are described which use sensitivity analyses and off‐axis data to determine the uniaxial strength of fiber composites. It was found that off‐axis composites failed by three fracture modes, which produce unique fracture surface characteristics. The stress that dominates each fracture mode and the load angle range of its dominance can be identified. Linear composite mechanics is adequate to describe quantitatively the mechanical behavior of off‐axis data are comparable to those measured in une

ISSN:0272-8397    

DOI:10.1002/pc.750020109

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

ISSN:0272-8397    

DOI:10.1002/pc.750020101

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY