scholarly journals A Probabilistic Model of the Unidirectional Tensile Strength of Fiber-Reinforced Polymers for Structural Design

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jianqing Zhang ◽  
Ruikun Zhang ◽  
Yihua Zeng
Keyword(s):  
Tensile Strength ◽  
Weibull Distribution ◽  
Probabilistic Model ◽  
Goodness Of Fit ◽  
Safety Margin ◽  
Reduction Factor ◽  
Fiber Reinforced Polymers ◽  
Statistical Uncertainty ◽  
Weibull Distributions ◽  
Frp Composites

In this paper, a statistical analysis of the tensile strength of FRP composites is conducted. A relatively large experimental database including 58 datasets is first constructed, and the Normal, Lognormal, and Weibull distributions are fitted to the data using a tail-sensitive Anderson–Darling statistic as the measure of goodness of fit. Fitting results show that the Normal, Lognormal, and Weibull distributions can be used to model the tensile strength of FRP composites. Then, the characteristic value for the tensile strength of FRP composites at a fixed percentile is analyzed. It is found that the Weibull distribution results in a higher safety margin in comparison to either the Normal or the Lognormal distribution. When the experimental justification, the theoretical justification, as well as the design conservativeness are taken into consideration, the Weibull distribution is the most recommended distribution to model the tensile strength of FRP composites. Furthermore, a probabilistic model considering the statistical uncertainty for the tensile strength for FRP composites is proposed. It is believed that the statistical uncertainty can be modeled as a reduction factor, and the recommended value of such factor for engineering design practices is provided based on regression analysis.

On the use of the Weibull distribution in modeling and describing diameter distributions of clonal eucalypt stands

2020 ◽  
Vol 50 (10) ◽  
pp. 1050-1063 ◽  
Author(s):  
Luciane Naimeke Schmidt ◽  
Mateus Niroh Inoue Sanquetta ◽  
John Paul McTague ◽  
Gilson Fernandes da Silva ◽  
Clayton Vieira Fraga Filho ◽  
...  
Keyword(s):  
Weibull Distribution ◽  
Goodness Of Fit ◽  
Cumulative Distribution ◽  
Growth And Yield ◽  
Likelihood Method ◽  
Weibull Distributions ◽  
Recovery Method ◽  
Stand Attributes ◽  
Parameter Prediction ◽  
Diameter Distributions

Weibull distributions have been widely used to describe tree stem diameter distributions. However, there is a scarcity of studies that suggest the best Weibull formulation. The parameters of the Weibull distribution are usually predicted by either the parameter prediction method (PPM) or the parameter recovery method (PRM), although other methods have been proposed. Thus, this study aimed to evaluate the performance of eight Weibull formulations and compare methods of parameter prediction to describe diameter distributions of clonal eucalypt stands in Brazil. Data originated from remeasurements of 56 plots at ages 3, 5, and 6 years. Weibull distributions were fitted using the maximum likelihood method and evaluated in a goodness-of-fit indicators ranking. The right-truncated two-parameter formulation showed the best results and was used to evaluate the methods of parameter prediction. Stand attributes showed a strong relationship with shape and scale parameters. Regression models were developed and resulted in accurate estimates using PPM. PRM used a growth and yield system to estimate the stand attributes, followed by the moment-based method. The modified cumulative distribution function regression (CDFR) approach was also evaluated, and it presented the poorest results. Although the PPM showed excellent results, PRM is recommended in older stands with inventory because it implicitly promotes compatibility among stand attributes.

scholarly journals 3D Printing of Fiber-Reinforced Plastic Composites Using Fused Deposition Modeling: A Status Review

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4520
Author(s):  
Salman Pervaiz ◽  
Taimur Ali Qureshi ◽  
Ghanim Kashwani ◽  
Sathish Kannan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
3D Printing ◽  
Fused Deposition Modeling ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Fused Deposition ◽  
Frp Composites ◽  
Deposition Modeling

Composite materials are a combination of two or more types of materials used to enhance the mechanical and structural properties of engineering products. When fibers are mixed in the polymeric matrix, the composite material is known as fiber-reinforced polymer (FRP). FRP materials are widely used in structural applications related to defense, automotive, aerospace, and sports-based industries. These materials are used in producing lightweight components with high tensile strength and rigidity. The fiber component in fiber-reinforced polymers provides the desired strength-to-weight ratio; however, the polymer portion costs less, and the process of making the matrix is quite straightforward. There is a high demand in industrial sectors, such as defense and military, aerospace, automotive, biomedical and sports, to manufacture these fiber-reinforced polymers using 3D printing and additive manufacturing technologies. FRP composites are used in diversified applications such as military vehicles, shelters, war fighting safety equipment, fighter aircrafts, naval ships, and submarine structures. Techniques to fabricate composite materials, degrade the weight-to-strength ratio and the tensile strength of the components, and they can play a critical role towards the service life of the components. Fused deposition modeling (FDM) is a technique for 3D printing that allows layered fabrication of parts using thermoplastic composites. Complex shape and geometry with enhanced mechanical properties can be obtained using this technique. This paper highlights the limitations in the development of FRPs and challenges associated with their mechanical properties. The future prospects of carbon fiber (CF) and polymeric matrixes are also mentioned in this study. The study also highlights different areas requiring further investigation in FDM-assisted 3D printing. The available literature on FRP composites is focused only on describing the properties of the product and the potential applications for it. It has been observed that scientific knowledge has gaps when it comes to predicting the performance of FRP composite parts fabricated under 3D printing (FDM) techniques. The mechanical properties of 3D-printed FRPs were studied so that a correlation between the 3D printing method could be established. This review paper will be helpful for researchers, scientists, manufacturers, etc., working in the area of FDM-assisted 3D printing of FRPs.

The use of Weibull Statistics to Quantify Property Variability in Fe-3Mn-0.8C Sinter-Hardened Structurally Inhomogeneous Steels

2013 ◽  
Vol 58 (4) ◽  
pp. 1045-1052 ◽  
Author(s):  
A. Cias ◽  
A. Czarski
Keyword(s):  
Tensile Strength ◽  
Weibull Distribution ◽  
Goodness Of Fit ◽  
Rupture Strength ◽  
Low Carbon ◽  
Weibull Statistics ◽  
Transverse Rupture Strength ◽  
Iron Powders ◽  
Goodness Of Fit Tests ◽  
Two Parameter

Abstract Low carbon ferro-manganese and graphite powders were admixed to Hoganas sponge, NC100.24, and water atomised, ABC 100.30 and ASC 100.29, iron powders - to produce three variants of sintered Fe-3Mn-0.8C steel. These were pressed into tensile and bend specimens at 660 MPa, sintered in semi-closed containers for 1 hour in dry nitrogen or hydrogen at 1120 or 1250°C and cooled at 64°C/min. Both tensile strength and transverse rupture strength were examined using Weibull statistics. This paper presents the results of a study to develop and evaluate goodness of fit tests for the two- and three-parameter Weibull distributions. The study was initiated because of discrepancies in published critical values for two-parameter Weibull distribution goodness of fit tests and the lack of general three-parameter Weibull distribution goodness of fit tests for properties of PM steels.

Study on Sequential Compliance Method Influenced by Shape Parameter of Weibull Distribution

2011 ◽  
Vol 189-193 ◽  
pp. 4361-4364 ◽  
Author(s):  
Hong Liang Lou ◽  
Xing Lin Li ◽  
Xian Zhao Xu ◽  
Yang Ping Zhang ◽  
Zhong Hua Yu
Keyword(s):  
Weibull Distribution ◽  
Shape Parameter ◽  
Weibull Distributions ◽  
Simulation Test ◽  
Consumer’S Risk ◽  
Producer’S Risk ◽  
Rejection Probability

When sequential compliance method is used for Weibull distributions, the shape parameter is usually considered to be fixed. However, because of the life of products are determined by many factors, the shape parameter is variational in practice, that is to say, the shape parameter in the criterions is different from that in the practice. In this paper, the changes of acceptance and rejection probability are researched by the influence of shape parameter changes. Finally, by means of simulation test, changes on the shape parameter affecting on the probability of acceptance and rejection are quantitatively analyzed. As a result, the larger the gap on the shape parameter in the criterions and in the practice is, the larger the gap on the producer’s risk and the consumer’s risk.

Research in Recycling Technology of Fiber Reinforced Polymers for Reduction of Environmental Load: Optimum Decomposition Conditions of Carbon Fiber Reinforced Polymers in the Purpose of Fiber Reuse

2011 ◽  
Vol 343-344 ◽  
pp. 142-149 ◽  
Author(s):  
Jian Shi ◽  
Kiyoshi Kemmochi ◽  
Li Min Bao
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Superheated Steam ◽  
Fiber Reinforced Polymers ◽  
Environmental Load ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Carbon Fiber Reinforced ◽  
Recycled Fibers

The objective of the present study is to investigate the effect of pyrolysis time and temperature on the mechanical properties of recycled carbon fiber, based on tensile strength measurements, determining the optimum decomposition conditions for carbon fiber-reinforced polymers (CFRPs) by superheated steam. In this research, CFRPs were efficiently depolymerized and reinforced fibers were separated from resin by superheated steam. Tensile strength of fibrous recyclates was measured and compared to that of virgin fiber. Although tensile strength of recycled fibers were litter lower than that of virgin fiber, under some conditions tensile strength of recycled fibers were close to that of virgin fiber. With pyrolysis, some char residue from the polymer remains on the fibers and degrees of char on the recycled fibers were closely examined by scanning electron microscopy.

Influence of Overheating Degree on Material Reliability of A390.0 Alloy

2012 ◽  
Vol 191 ◽  
pp. 23-28 ◽  
Author(s):  
Jaroslaw Piątkowski
Keyword(s):  
Tensile Strength ◽  
Distribution Function ◽  
Weibull Distribution ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Time To Failure ◽  
The Impact ◽  
Failure Evaluation ◽  
Graphic Interpretation ◽  
Gravity Cast

The object of the studies was A390.0 alloy (AlSi17Cu5Mg), similar to A3XX.X series, gravity cast into sand and metal moulds. This alloy is mainly used for cast pistons operating in I.C. engines, for cylinder blocks and housings of compressors, and for pumps and brakes. The A390.0 alloy was poured at temperatures 880 and 980°C, holding the melt for 30 minutes and casting from the temperature of 780°C. The assessment of the impact of the degree of overheating was to analysis the tensile strength. Studies were carried out on a normal-running fatigue testing machine, which was the mechanically driven resonant pulsator. For the needs of quantitative reliability evaluation and the time-to-failure evaluation, the procedures used in survival analysis, adapted to the analysis of failure-free operation with two-parametric Weibull distributions, were applied. Having determined the boundary value σ0 for Weibull distribution, the value of „m” modulus was computed along with other coefficients of material reliability, proposed formerly by the authors. Basing on the obtained results, a model of Weibull distribution function was developed for the tensile strength with respective graphic interpretation.

Wind speed distribution modeling for wind power estimation: Case of Agadir in Morocco

2018 ◽  
Vol 43 (2) ◽  
pp. 190-200 ◽  
Author(s):  
Ijjou Tizgui ◽  
Fatima El Guezar ◽  
Hassane Bouzahir ◽  
Brahim Benaid
Keyword(s):  
Wind Speed ◽  
Wind Energy ◽  
Weibull Distribution ◽  
Wind Power ◽  
Goodness Of Fit ◽  
Statistical Tests ◽  
A Priori ◽  
Speed Distribution ◽  
Distribution Modeling ◽  
Wind Speed Distribution

To estimate a wind turbine output, optimize its dimensioning, and predict the economic profitability and risks of a wind energy project, wind speed distribution modeling is crucial. Many researchers use directly Weibull distribution basing on a priori acceptance. However, Weibull does not fit some wind speed regimes. The goal of this work is to model the wind speed distribution at Agadir. For that, we compare the accuracy of four distributions (Weibull, Rayleigh, Gamma, and lognormal) which have given good results in this yield. The goodness-of-fit tests are applied to select the effective distribution. The obtained results explain that Weibull distribution is fitting the histogram of observations better than the other distributions. The analysis deals with comparing the error in estimating the annual wind power density using the examined distributions. It was found that Weibull distribution presents minimum error. Thus, wind energy assessors in Agadir can use directly Weibull distribution basing on a scientific decision made via statistical tests. Moreover, assessors worldwide can use the followed methodology to model their wind speed measurements.

scholarly journals Recurrent frequency-size distribution of characteristic events

2009 ◽  
Vol 16 (2) ◽  
pp. 333-350 ◽  
Author(s):  
S. G. Abaimov ◽  
K. F. Tiampo ◽  
D. L. Turcotte ◽  
J. B. Rundle
Keyword(s):  
Weibull Distribution ◽  
Passage Time ◽  
Time Interval ◽  
Weibull Distributions ◽  
Event Sequences ◽  
San Andreas ◽  
Statistical Frequency ◽  
Earthquake Sequences ◽  
Best Fit ◽  
Frequency Magnitude

Abstract. Statistical frequency-size (frequency-magnitude) properties of earthquake occurrence play an important role in seismic hazard assessments. The behavior of earthquakes is represented by two different statistics: interoccurrent behavior in a region and recurrent behavior at a given point on a fault (or at a given fault). The interoccurrent frequency-size behavior has been investigated by many authors and generally obeys the power-law Gutenberg-Richter distribution to a good approximation. It is expected that the recurrent frequency-size behavior should obey different statistics. However, this problem has received little attention because historic earthquake sequences do not contain enough events to reconstruct the necessary statistics. To overcome this lack of data, this paper investigates the recurrent frequency-size behavior for several problems. First, the sequences of creep events on a creeping section of the San Andreas fault are investigated. The applicability of the Brownian passage-time, lognormal, and Weibull distributions to the recurrent frequency-size statistics of slip events is tested and the Weibull distribution is found to be the best-fit distribution. To verify this result the behaviors of numerical slider-block and sand-pile models are investigated and the Weibull distribution is confirmed as the applicable distribution for these models as well. Exponents β of the best-fit Weibull distributions for the observed creep event sequences and for the slider-block model are found to have similar values ranging from 1.6 to 2.2 with the corresponding aperiodicities CV of the applied distribution ranging from 0.47 to 0.64. We also note similarities between recurrent time-interval statistics and recurrent frequency-size statistics.

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