Composites EngineeringPub Date : 1995-01-01Epub Date: 2008-07-14DOI: 10.1016/0961-9526(94)00063-F
Paul D. Herrington
{"title":"Stress-strength interference theory for a pin-loaded composite joint","authors":"Paul D. Herrington","doi":"10.1016/0961-9526(94)00063-F","DOIUrl":"10.1016/0961-9526(94)00063-F","url":null,"abstract":"<div><p>Considering the increasing applications of composites as structural components, the reliability of these materials is an important issue. In this paper, stress-strength interference theory is used to determine the reliability of a component that is characterized having a Weibull strength distribution and is under the effects of an applied load that is not deterministic, but follows a probability distribution. The assumption that failure is caused by the maximum of a sequence of applied loads is the basis for describing the applied load distribution as a Gumbel Type 1 extreme value distribution. Reliability plots are given for a class of strength parameters that are typical of graphite/epoxy laminates. A numerical example for a pin-loaded composite laminate is shown using experimentally obtained data.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 8","pages":"Pages 975-982"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(94)00063-F","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89280983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Composites EngineeringPub Date : 1995-01-01Epub Date: 2008-07-14DOI: 10.1016/0961-9526(94)00080-S
A.E. Bogdanovich, C.M. Pastore, B.P. Deepak
{"title":"A comparison of various 3-D approaches for the analysis of laminated composite structures","authors":"A.E. Bogdanovich, C.M. Pastore, B.P. Deepak","doi":"10.1016/0961-9526(94)00080-S","DOIUrl":"10.1016/0961-9526(94)00080-S","url":null,"abstract":"<div><p>Three computational approaches for 3-D analysis of laminated composite plates are presented. These are displacement assumed approach, displacement assumed/equilibrium approach and mixed two-field approach. The fundamental concept in all of the three approaches is that “deficient” polynomials have to be used for the through-the-thickness displacement approximation. Bernstein polynomials, having discontinuous first derivatives at the interfaces, are used as approximation functions in the through-the-thickness direction. The examples of a double-sine distributed surface load on 3-ply, 9-ply, and sandwich plates examined by Pagano are solved. It is shown that the results obtained with all three present approaches agree excellently with the closed form solution, for the length-to-thickness aspect ratios ranging from 2–100. A comparison between the results obtained with the deficient and with the continuously differentiable displacement approximations is also presented. This reveals that polynomial approximations that are continuously differentiable through the whole thickness of a laminate, provide qualitatively incorrect transverse stresses at the interfaces. By increasing the degree of the polynomial, one gets two distinct <em>from the top</em> and <em>from the bottom</em> limits for any transverse stress component on the interfaces. On the contrary, when using deficient approximation functions one obtains the same <em>from the top</em> and <em>from the bottom</em> limits for the transverse stresses on the interfaces.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 9","pages":"Pages 1105-1126"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(94)00080-S","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87361068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Composites EngineeringPub Date : 1995-01-01Epub Date: 2008-07-14DOI: 10.1016/0961-9526(95)00074-W
Krishnan Balasubramaniam, Satyanarayana Alluri, Praveen Nidumolu, P.Raju Mantena, James G. Vaughan, Murthy Kowsika
{"title":"Ultrasonic and vibration methods for the characterization of pultruded composites","authors":"Krishnan Balasubramaniam, Satyanarayana Alluri, Praveen Nidumolu, P.Raju Mantena, James G. Vaughan, Murthy Kowsika","doi":"10.1016/0961-9526(95)00074-W","DOIUrl":"10.1016/0961-9526(95)00074-W","url":null,"abstract":"<div><p>Characterization of unidirectional fiber reinforced glass/epoxy pultruded composites using ultrasonics (high frequency, 1-5 MHz) and the impulse-frequency response vibration (intermediate frequency, 50-100 Hz) technique, is demonstrated here. This paper compares the response of both of these non-destructive test techniques to the changes in the pultrusion process variables and to the indeed contaminants introduced during manufacturing. The ultrasonic methods use multi-mode techniques of wave velocity and attenuation measurements to measure the viscoelastic constants of the pultruded composite while the vibration technique provides the dynamic flexural modulus and loss factor (damping) measurements. Quasi-destructive assays were also performed using a low frequency (1-50 Hz) Dynamic Mechanical Analyser (DMA) to verify the state of pultruded samples with induced contaminants (simulated porosity and interfacial debonding) and the results compared with the non-destructive measurements. Mathematical models to describe the influence of porosity and debonding agents on the material properties were derived based on statistical regression analysis procedures. Results indicate that the peak damping value of the tan δ curve obtained from the DMA is a sensitive parameter to detect abnormalities in the finished product. The ultrasonic velocity and dynamic flexural modulus measurements provide useful information on the stiffness characteristics while the attention and loss factor can be related to the anomaly-sensitive damping properties of the material.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 12","pages":"Pages 1433-1451"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(95)00074-W","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88812795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Composites EngineeringPub Date : 1995-01-01Epub Date: 2008-07-14DOI: 10.1016/0961-9526(95)00049-S
J.K. Chen, A. Perea, F.A. Allahdadi
{"title":"Laser effects on the dynamic response of laminated composites","authors":"J.K. Chen, A. Perea, F.A. Allahdadi","doi":"10.1016/0961-9526(95)00049-S","DOIUrl":"https://doi.org/10.1016/0961-9526(95)00049-S","url":null,"abstract":"<div><p>Transient response of a moving composite laminate suddenly subjected to combined mechanical load and high intensity laser irradiation was investigated. The three thermal effects, which are caused by rapid laser heating and influence the structure's dynamic behavior, are material property degradation, burn-out and induced thermal loading. To determine temperature distribution and material burn-out due to the high laser energy deposition, a modified Crank-Nicholson finite difference scheme, which includes the effects of surface ablation, degradation of thermophysical properties at elevated temperatures and heat losses from radiation and convection, was employed. The predicted thermal results were then used for thermal loading calculation and, subsequently, forced vibration analysis. Both small and large deflection composite plate theories were adopted. The inclusion of temperature-dependent mechanical properties in the analysis was also of particular importance. It was shown that the escalation or reduction of vibration response of a laminated composite subjected to transverse loads by laser irradiation depends not only upon the laser intensity, but also, which plate surface is irradiated. It was also found that a higher power laser irradiation ensures neither greater escalation not reduction of the vibration.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 9","pages":"Pages 1135-1147"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(95)00049-S","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91754484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Composites EngineeringPub Date : 1995-01-01Epub Date: 2008-07-14DOI: 10.1016/0961-9526(95)00043-M
Frank J. Rooney, M. Ferrari
{"title":"Torsion and flexure of inhomogeneous elements","authors":"Frank J. Rooney, M. Ferrari","doi":"10.1016/0961-9526(95)00043-M","DOIUrl":"10.1016/0961-9526(95)00043-M","url":null,"abstract":"<div><p>The torsion of bars with inhomogeneous shear moduli is considered, under different assumptions on the cross-sectional geometry, and the spatial variation law for the moduli. In particular, bars of arbitrary geometry, and modulus that varies in the section only through a function of the coordinates are considered, under the additional assumption that the modulus is constant on the sectional boundary. Bounds on the torsional rigidity are established. As special cases, laminates are discussed, and novel solutions for the torsion of a circular cylindrical bar with angular symmetry are presented. The problem of flexure of inhomogeneous cylindrical bars is considered, allowing for arbitrary variation of the moduli but with constant Poisson's ratio. Specific solutions are exhibited for the case of angular and radial variations of the shear modulus. Finally, the derived solutions are employed to determine the effective properties of the graded structures.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 7","pages":"Pages 901-911"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(95)00043-M","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90183572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Composites EngineeringPub Date : 1995-01-01Epub Date: 2008-07-14DOI: 10.1016/0961-9526(95)93976-3
L. Daudeville , O. Allix , P. Ladevèze
{"title":"Delamination analysis by damage mechanics: Some applications","authors":"L. Daudeville , O. Allix , P. Ladevèze","doi":"10.1016/0961-9526(95)93976-3","DOIUrl":"10.1016/0961-9526(95)93976-3","url":null,"abstract":"<div><p>Delamination is a phenomenon which involves complex degradation of both layers and inter-laminar connections. To take into account these degradations, the composite laminate is modeled at a meso scale as a stacking of homogeneous layers connected by interfaces. Layers and interfaces may be damaged. Both onset of delamination and its propagation on a short distance are predicted. Two applications are presented, the numerical simulations are compared with experimental results: (i) delamination in the vicinity of a straight edge of a specimen under tension or compression, (ii) delamination near the hole of a perforated plate under tension.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 1","pages":"Pages 17-24"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(95)93976-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85261390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Composites EngineeringPub Date : 1995-01-01Epub Date: 2008-07-14DOI: 10.1016/0961-9526(95)00075-X
R.K.N.D. Rajapakse, D. Gross
{"title":"Transient displacements of a composite medium with defects due to a surface pulse","authors":"R.K.N.D. Rajapakse, D. Gross","doi":"10.1016/0961-9526(95)00075-X","DOIUrl":"10.1016/0961-9526(95)00075-X","url":null,"abstract":"<div><p>This paper considers the transient dynamic response of a composite medium with arbitrary shaped voids. A boundary integral equation method is used to compute the displacement histories due to a loading pulse applied to the surface of a composite medium. The present methodology can also be used to study the response of a medium with near-surface cracks and elastic impurities. Numerical solutions are presented for graphite/epoxy, glass/epoxy and isotropic media. The influence of the degree of anisotropy of a medium, orientation and geometry of a void, time history of the loading pulse and the interaction between multiple voids are examined. It is found that the near-field displacements of a damaged medium differ substantially from an undamaged medium. The results reported here can be used for qualitative and quantitative nondestructive evaluations and also for computing the acoustic material signature of a composite medium with defects. The present results are also useful in the validation of inverse solution algorithms developed for material characterization.</p></div>","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 12","pages":"Pages 1519-1536"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(95)00075-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87656420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Composites EngineeringPub Date : 1995-01-01Epub Date: 2008-07-14DOI: 10.1016/0961-9526(95)00056-S
B. Mobasher, Cheng Yu Li
{"title":"Modeling of stiffness degradation of the interfacial zone during fiber debonding","authors":"B. Mobasher, Cheng Yu Li","doi":"10.1016/0961-9526(95)00056-S","DOIUrl":"https://doi.org/10.1016/0961-9526(95)00056-S","url":null,"abstract":"","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 10","pages":"1349-1365"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(95)00056-S","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72246604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Composites EngineeringPub Date : 1995-01-01Epub Date: 2008-07-14DOI: 10.1016/0961-9526(95)00055-R
H. Ho, L.T. Drzal
{"title":"Non-linear numerical study of the single-fiber fragmentation test. Part II: A parametric study","authors":"H. Ho, L.T. Drzal","doi":"10.1016/0961-9526(95)00055-R","DOIUrl":"https://doi.org/10.1016/0961-9526(95)00055-R","url":null,"abstract":"","PeriodicalId":100298,"journal":{"name":"Composites Engineering","volume":"5 10","pages":"1245-1259"},"PeriodicalIF":0.0,"publicationDate":"1995-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0961-9526(95)00055-R","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72246607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}