Reliability Analysis of FRP Laminated Plates With Initial Imperfection

2002 ◽  
Author(s):  
Jianqiao Chen ◽  
Xiangyang Wang ◽  
Cheng Luo
Keyword(s):  
Failure Probability ◽  
Progressive Failure ◽  
Laminated Composite ◽  
Initial Imperfection ◽  
Strength Criterion ◽  
Laminated Plates ◽  
System Failure ◽  
Strength Parameters ◽  
Compression Load ◽  
Reliability Method

In this paper, a probabilistic progressive failure analysis method is applied to estimating the reliability of a simply supported laminated composite plate with an initial imperfection under bi-axial compression load. The initial imperfection and the strength parameters are considered as random variables. Ply-level failure probability is evaluated by the first order reliability method (FORM) together with the Tsai-Wu strength criterion and Tan criterion. Current stresses in the laminated structure are calculated by classical lamination theory with the stiffness being modified based on the last step ply failure. Probabilistieally dominant ply-level failure sequences leading to overall system failure are identified by branch and bound method. The system failure probability is estimated through the union of significant failure sequences. A numerical example is presented to demonstrate the methodology proposed. Parameter studies show that the deviation of the initial imperfection and strength parameters largely influence the system reliability.

Stochastic aeroelastic analysis of laminated composite plate with variable fiber spacing

2021 ◽  
pp. 002199832110408
Author(s):  
Narayan Sharma ◽  
Prasant Kumar Swain ◽  
Dipak Kumar Maiti ◽  
Bhrigu Nath Singh
Keyword(s):  
Perturbation Technique ◽  
Laminated Composite ◽  
Distribution Patterns ◽  
Laminated Plates ◽  
Fiber Distribution ◽  
Various Boundary Conditions ◽  
Aeroelastic Analysis ◽  
Fiber Spacing ◽  
Reliability Method ◽  
Parametric Studies

In this paper, the dynamic and aeroelastic analysis of variable fiber spacing composite (VFSC) laminated plates are carried out. The effects and benefits of changing the fiber distribution pattern on natural frequency and mode shape are explored taking various boundary conditions. Taking cantilever boundary condition flutter characteristics of VFSC plate with different fiber distribution patterns are compared. Further stochasticity of flutter velocity due to randomness in material properties that could arise due to complex manufacturing and fabrication process of VFSC laminates is investigated. The perturbation technique is implemented to perform the stochastic as well as reliability analysis. Various parametric studies are conducted to check the accuracy and efficiency of perturbation technique, by comparing the results with that of Monte Carlo simulation and the first-order reliability method.

Single-Loop System Reliability-Based Design Optimization Using Matrix-Based System Reliability Method: Theory and Applications

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Tam H. Nguyen ◽  
Junho Song ◽  
Glaucio H. Paulino
Keyword(s):  
Design Optimization ◽  
Failure Probability ◽  
System Reliability ◽  
Loop System ◽  
Probabilistic Constraints ◽  
System Failure ◽  
Reliability Based Design Optimization ◽  
Single Loop ◽  
Reliability Based Design ◽  
Reliability Method

This paper proposes a single-loop system reliability-based design optimization (SRBDO) approach using the recently developed matrix-based system reliability (MSR) method. A single-loop method was employed to eliminate the inner-loop of SRBDO that evaluates probabilistic constraints. The MSR method enables us to compute the system failure probability and its parameter sensitivities efficiently and accurately through convenient matrix calculations. The SRBDO/MSR approach proposed in this paper is applicable to general systems including series, parallel, cut-set, and link-set system events. After a brief overview on SRBDO algorithms and the MSR method, the SRBDO/MSR approach is introduced and demonstrated by three numerical examples. The first example deals with the optimal design of a combustion engine, in which the failure is described as a series system event. In the second example, the cross-sectional areas of the members of a statically indeterminate truss structure are determined for minimum total weight with a constraint on the probability of collapse. In the third example, the redistribution of the loads caused by member failures is considered for the truss system in the second example. The results based on different optimization approaches are compared for further investigation. Monte Carlo simulation is performed in each example to confirm the accuracy of the system failure probability computed by the MSR method.

scholarly journals Interfacial Morphology and Bonding Mechanism of Explosive Weld Joints

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Tingting Zhang ◽  
Wenxian Wang ◽  
Zhifeng Yan ◽  
Jie Zhang
Keyword(s):  
Laminated Composite ◽  
Base Plate ◽  
Sine Wave ◽  
Laminated Plates ◽  
Bonding Interface ◽  
Interfacial Structure ◽  
Bonding Mechanism ◽  
Critical Material ◽  
Interfacial Morphology ◽  
Az31b Alloy

AbstractInterfacial structure greatly affects the mechanical properties of laminated plates. However, the critical material properties that impact the interfacial morphology, appearance, and associated bonding mechanism of explosive welded plates are still unknown. In this paper, the same base plate (AZ31B alloy) and different flyer metals (aluminum alloy, copper, and stainless steel) were used to investigate interfacial morphology and structure. SEM and TEM results showed that typical sine wave, wave-like, and half-wave-like interfaces were found at the bonding interfaces of Al/Mg, Cu/Mg and SS/Mg clad plates, respectively. The different interfacial morphologies were mainly due to the differences in hardness and yield strength between the flyer and base metals. The results of the microstructural distribution at the bonding interface indicated metallurgical bonding, instead of the commonly believed solid-state bonding, in the explosive welded clad plate. In addition, the shear strength of the bonding interface of the explosive welded Al/Mg, Cu/Mg and SS/Mg clad plates can reach up to 201.2 MPa, 147.8 MPa, and 128.4 MPa, respectively. The proposed research provides the design basis for laminated composite metal plates fabrication by explosive welding technology.

Dynamic Characterization and Modeling of Carbon Composite Ballistic Behavior

2016 ◽  
Author(s):  
Chian-Fong Yen ◽  
Robert Kaste ◽  
Jian Yu ◽  
Charles Chih-Tsai Chen ◽  
Nelson Carey
Keyword(s):  
Composite Material ◽  
Progressive Failure ◽  
Laminated Composite ◽  
Carbon Composite ◽  
Ballistic Impact ◽  
Impact Testing ◽  
Material Behavior ◽  
Failure Behavior ◽  
Failure Model ◽  
Carbon Composite Material

Design of the new generation of aircraft is driven by the vastly increased cost of fuel and the resultant imperative for greater fuel efficiency. Carbon fiber composites have been used in aircraft structures to lower weight due to their superior stiffness and strength-to-weight properties. However, carbon composite material behavior under dynamic ballistic and blast loading conditions is relatively unknown. For aviation safety consideration, a computational constitutive model has been used to characterize the progressive failure behavior of carbon laminated composite plates subjected to ballistic impact conditions. Using a meso-mechanics approach, a laminated composite is represented by a collection of selected numbers of representative unidirectional layers with proper layup configurations. The damage progression in a unidirectional layer is assumed to be governed by the strain-rate dependent layer progressive failure model using the continuum damage mechanics approach. The composite failure model has been successfully implemented within LS-DYNA as a user-defined material subroutine. In this paper, the ballistic limit velocity (V50) was established for a series of laminates by ballistic impact testing. Correlation of the predicted and measured V50 values has been conducted to validate the accuracy of the ballistic modeling approach for the selected carbon composite material. The availability of this modeling tool will greatly facilitate the development of carbon composite structures with enhanced ballistic and blast survivability.

scholarly journals Derived Interaction Parameters for the TSAI-WU Tensor Polynomial Theory of Strength for Composite Materials

2001 ◽  
Author(s):  
Steven J. DeTeresa ◽  
Gregory J. Larsen
Keyword(s):  
Hydrostatic Pressure ◽  
Fiber Composite ◽  
Strength Criterion ◽  
Test Methods ◽  
Standard Test ◽  
Transverse Compression ◽  
Strength Parameters ◽  
Carbon Fiber Composite ◽  
The Stability ◽  
Stability Limits

Abstract It is shown that the two interactive strength parameters in the Tsai-Wu tensor polynomial strength criterion for fiber composites can be derived in terms of the uniaxial or non-interacting strength parameters if the composite does not fail under practical levels of hydrostatic pressure or equal transverse compression. Thus the required number of parameters is reduced from seven to five and all five of the remaining strength terms are easily determined using standard test methods. The derived interactive parameters fall within the stability limits of the theory, yet they lead to open failure surfaces in the compressive stress quadrant. The assumptions used to derive the interactive parameters were supported by measurements for the effect of hydrostatic pressure and unequal transverse compression on the behavior of a typical carbon fiber composite.

Reliability of Buried Pipeline Using a Theory of Probability of Failure

2006 ◽  
Vol 110 ◽  
pp. 221-230 ◽  
Author(s):  
Ouk Sub Lee ◽  
Dong Hyeok Kim ◽  
Seon Soon Choi
Keyword(s):  
Failure Probability ◽  
Probability Of Failure ◽  
Operating Conditions ◽  
Reliability Estimation ◽  
Design Parameters ◽  
Buried Pipeline ◽  
Safety Level ◽  
First Order ◽  
Reliability Method ◽  
Corrosion Defects

The reliability estimation of buried pipeline with corrosion defects is presented. The reliability of corroded pipeline has been estimated by using a theory of probability of failure. And the reliability has been analyzed in accordance with a target safety level. The probability of failure is calculated using the FORM (first order reliability method). The changes in probability of failure corresponding to three corrosion models and eight failure pressure models are systematically investigated in detail. It is highly suggested that the plant designer should select appropriate operating conditions and design parameters and analyze the reliability of buried pipeline with corrosion defects according to the probability of failure and a required target safety level. The normalized margin is defined and estimated accordingly. Furthermore, the normalized margin is used to predict the failure probability using the fitting lines between failure probability and normalized margin.

Reliability Method to Estimate Shear Strength Parameters

2011 ◽  
Vol 52-54 ◽  
pp. 1752-1756
Author(s):  
Li Hong Chen ◽  
Yu Fei Zhao
Keyword(s):  
Shear Strength ◽  
Linear Regression ◽  
Moment Method ◽  
Limit State ◽  
Safety Evaluation ◽  
Regression Method ◽  
Linear Regression Method ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Reliability Method

The design and safety evaluation of a geotechnical project is influenced by the shear strength parameters of geo-material. Moment method and linear regression method are the mainly used methods to estimate the shear strength parameters. But moment method is always over estimate the variation of strength parameters due to the smaller sample size, meanwhile the conventional linear regression method cannot obtain the standard deviation. Base on the reliability theory, a new method employing Solver add-in of spreadsheet was developed to calculate the shear strength parameters. The method was simplified by the principle that the shortest distance form origin point to the limit state surface in the normalization space was the reliability index. Four hundred and four samples of direct shear tests of rock mass from many large hydraulic projects in China were analyzed by four statistic methods including the new proposed one. Comparing results of different methods indicated that the new reliability statistic method had good performance than the traditional ways.

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