摘要:

AbstractThe Improvement of the tensile strength of discontinuous graphite fiber‐reinforced polypropylene is described. Two methods were employed: (1) modification of the polymer backbone by the introduction of acrylic acid grafts and (2) varying the chemistry of the fiber sizing. The strength improvements attained are attributed to intermolecular interactions, such as hydrogen bonding, which improve the adhesion between the fiber and the polyme

ISSN:0272-8397    

DOI:10.1002/pc.750020302

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe Mechanical properties of injection molded and compression molded graphite fiber‐reinforced polypropylenes are discussed. In general, the tensile properties of polypropylene are significantly improved by reinforcement with graphite fibers and to a greater extent than achieved by glass fiber reinforcement. The failure mechanism of these materials involved a combination of matrix fracture and debonding of the fiber‐polymer interface. The use temperature of these materials is shown to increase with increasing fiber content and the notch sensitivity is redu

ISSN:0272-8397    

DOI:10.1002/pc.750020303

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractIn this report, a theoretical examination is made of the life span of polymer concrete (PC) composites in aggressive environments. Using well known physical chemistry laws, in can be shown that the durability of PC is dependent only on the temperature and concentration of the aggressive environment. This dependence can be extremely useful to potential users of PC materials in aggressive environments since the life span of such materials may be predicted with minimum experimental data.

ISSN:0272-8397    

DOI:10.1002/pc.750020304

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractA numerical model of passive thermal nondestructive evaluation (NDE) of composite laminates was developed. This model, based on a transient, three‐dimensional, finite difference solution to the heat conduction equations, can be used to characterize in‐plane defects in the laminates and to predict the laminate response to the thermal test. The model was experimentally verified using two material systems. A parametric study was then conducted to ascertain which variables were critical to the success of passive thermal NDE, and how flaw resolution might be impro

ISSN:0272-8397    

DOI:10.1002/pc.750020305

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe weibull brittle failure model is used to described the tensile strength degradation of a fiber‐reinforced composite material in the presence of a notch. This model uses the description of the state of stress near the notch and the Weibull shape parameter from a series of unnotched tensile tests. The Weibull‐model strengtyh degradation is evaluated using numerical integration of a reduced, one‐dimensional tensile volume. The numberical Weibull integral results are compared with the point stress failure theory. The comparison suggests that the two parameters of the point stress theory stem form the single Weibull shape parameter. The integral results are shown to be conservative when compared with data for two graphite. epoxy sy

ISSN:0272-8397    

DOI:10.1002/pc.750020306

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe viscoelastic behavior of epoxy composites containing various percentage of glass microspheres and random short glass fibers was investigated over a wide range of temperatures. The effect of the second phase is to increase the relaxation moduli of the system and to shift the time dependency to higher times. All the data were shifted to a single master curve at a reference temperature by using independent shift factors that were a function of either temperature or filler content.

ISSN:0272-8397    

DOI:10.1002/pc.750020307

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThis paper describes a torsion pendulum based on the free vibration method and designed for studies on tubular samples. The design and fabrication of the injection mold used for molding the tubular specimens is also described. Tubular specimens were injection molded form polypropylene and glass fiber‐reinforced polypropylene having different glass fiber contents. The sample, which is enclosed in an insulated chamber, can be cooled with the help of liquid nitrogen and heated electrically. The damped oscillations were recorded on a moving chart paper using a lamp and a photodyne between −40 to 100°C. The results indicate that both storage modulus and the logarithmic decrement are affected by the glass fiber and its content. The reinforcing effect of glass fiber and the suppression of viscoelastic effects are briefly discu

ISSN:0272-8397    

DOI:10.1002/pc.750020308

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe goal of this series of reports is to develop rapid computational procedures for determining the rearrangement of fibers that occurs during the molding of continuous fiber composite components for flat layups. This report considers the shaping of a cloth into a hemisphere. /the numerical procedure developed predicts that a cloth can be shaped into a hemisphere without wrinkling. This prediction is compared with experiment, and various paramenters connected with the shaping calculation are discussed.

ISSN:0272-8397    

DOI:10.1002/pc.750020309

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractMoisture penetration at 95°C into glass fiber and graphite fiber‐reinforced epoxies is examined in stressed and unstressed materials. The study focuses on the effect of the angle between the stress and the fiber directions on the diffusivities. It is found that the consequence of applying external stresses to composites is an increase in their rate of moisture absorption, their maximum moisture content, and in the diffusion coefficients. As the angle between the loading and fiber directions in increased the rate and the maximum value of moisture absorption also increase. Their ratio, however, remains constant resulting in loading angle independence of the exposure of the composites to water produces a typical damage mechanism which enhances moisture take

ISSN:0272-8397    

DOI:10.1002/pc.750020310

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY

摘要:

AbstractCyclic tension fatigue S‐N curves are given for injection moleded Nylon 6/6, polycarbonate, polysulfone, polyphenylene sulfide, and poly(amide‐imide) matrices with glass and carbon fibers as well as for unreinforced material. The S‐N curves for most composites appear linear, with no evidence of a fatigue limit up to 106cycles. Some nonlinearity is evident with the Nylon 6/6 composities, and these appear to fail at a cumulative strain similar to the ultimate static strain. The remainder of the composites appear to fail by a crack propagation mechanism. The glass reinforced materials all degrade at a similar rate in fatigue, while the carbon reinforced materials with brittle matrices degrade more slowly than do those with ductile matrices. The latter effect may be due to greater integrity of the cracked regions for brittle matrix sy

ISSN:0272-8397    

DOI:10.1002/pc.750020311

出版商:Society of Plastics Engineers, Inc.    

年代:1981

数据来源: WILEY