scholarly journals Reliability Analysis of a Solid Timber Column Subjected to Axial and Lateral Loading

2019 ◽  
Vol 4 (2) ◽  
Author(s):  
Sule Samuel ◽  
M J Benu
Keyword(s):  
Reliability Analysis ◽  
Failure Modes ◽  
Slenderness Ratio ◽  
Load Ratio ◽  
Failure Criteria ◽  
Lateral Loading ◽  
Reliability Indices ◽  
Reliability Method ◽  
Timber Column ◽  
Bending Failure

In this paper, a reliability analysis of a solid timber column of square cross section subjected to axial and lateral loading in accordance with the design requirements of Eurocode 5 is carried out. Compression and bending were the two failure criteria considered in the reliability investigation. The First Order Reliability method was employed to solve the limit state functions formed from the two failure criteria and was coded in MATLAB for quick estimation of the reliability indices. The results obtained showed that both the load and slenderness ratios have effects on the reliability of a solid timber column. The results of the sensitivity analysis carried out on the stochastic variables showed that the reliability indices decreased with increase in slenderness ratio for 3m, 4m and 5m length of column considering both the compression and bending failure modes and decreased with increase in load ratio for 3m, 4m and 5m length of column considering both the compression and bending failure modes. The reliability indices also decreased with increase in length of column mode and decreased with increase in ratio considering bending failure mode. The reliability indices were also found to decrease with increase in load ratio for varying values of axial and lateral loads at constant slenderness ratio and length of column considering compression and bending failure modes. The choice of adequate and suitable dimensions having a lower slenderness ratio will enhance the reliability of the column. Keywords- Reliability analysis, solid timber column, Eurocode 5, failure criteria, slenderness ratio 

Reliability analysis of wood I-joists

1993 ◽  
Vol 20 (4) ◽  
pp. 564-573 ◽  
Author(s):  
R. O. Foschi ◽  
F. Z. Yao
Keyword(s):  
Reliability Analysis ◽  
Carrying Capacity ◽  
Failure Modes ◽  
Limit State ◽  
Load Carrying Capacity ◽  
Limit States ◽  
Element Analysis ◽  
Strength Limit ◽  
Reliability Method ◽  
Load Carrying

This paper presents a reliability analysis of wood I-joists for both strength and serviceability limit states. Results are obtained from a finite element analysis coupled with a first-order reliability method. For the strength limit state of load-carrying capacity, multiple failure modes are considered, each involving the interaction of several random variables. Good agreement is achieved between the test results and the theoretical prediction of variability in load-carrying capacity. Finally, a procedure is given to obtain load-sharing adjustment factors applicable to repetitive member systems such as floors and flat roofs. Key words: reliability, limit state design, wood composites, I-joist, structural analysis.

Experimental and numerical investigation of fatigue damage accumulation in composite laminates

2015 ◽  
Vol 26 (6) ◽  
pp. 840-858 ◽  
Author(s):  
Soran Hassanifard ◽  
Mohsen Feyzi
Keyword(s):  
Fatigue Life ◽  
Composite Laminates ◽  
Failure Modes ◽  
Three Dimensional ◽  
Load Ratio ◽  
Element Model ◽  
Failure Criteria ◽  
Damage Parameter ◽  
Fatigue Damage Accumulation ◽  
Three Dimensional Finite Element

In this study, a three-dimensional finite element model was developed to predict the fatigue life of composite bolted joints. In this model, progressive damage theory was used. The fatigue characterization was based on Hashin’s failure criteria which recognize the failure modes. To decrease the number of unidirectional tests, the effects of load ratio were considered based on Kawai’s criterion. A modified form of Miner’s rule was proposed to calculate the damage parameter. This equation corrected the effects of the fatigue failure cycles and included the effects of different load ratios. Also, this model could decrease the overestimation of the fatigue life predictions. All of the formulations were combined and used in a step-by-step solution. In this respect, a new iterative algorithm was developed so that at each step of solution, the material properties of all failed layers of each element were reduced according to the failure mode and sudden degradation rules. The estimated fatigue life was compared to the experimental data, and an excellent correlation between the results was observed. This model could monitor the damage propagation in fabricated joints.

scholarly journals Reliability Analysis of Anchored Geotechnical Structures for the Design Limit States

2020 ◽  
Vol 8 (2) ◽  
pp. 35-47
Author(s):  
Sohaib K Al-Mamoori ◽  
Laheab A. Al-Maliki ◽  
Khaled El-Tawel
Keyword(s):  
Reliability Analysis ◽  
Reliability Index ◽  
Failure Modes ◽  
Limit State ◽  
Tensile Failure ◽  
Limit States ◽  
Geotechnical Parameters ◽  
Retaining Structure ◽  
Geotechnical Structures ◽  
Bending Failure

Reliability has been considered of magnificent importance in engineering design specially in geotechnical engineering due to the unpredictable conditions of soil layers. It is essential to establish well- designed failure modes that could guarantee safety and durability of the proposed structure. This study aims to suggest a reliability analyses procedure for retaining walls by the mean of a reliability index β using the specifications of AASHTO Bridge Design 2002, Eurocode 7, and DIN EN 1993-5 norms. Two failure modes; Tensile failure of tendon (G1) and Failure by bending (G2) were studied and compared by using equation of the Design Limit State (DLS) and by taking some basic geotechnical parameters as Random Variables RV. The analyses demonstrated that the reliability index β and probability of failure Pf are the most important parameter in the reliability analysis. Also, the suitable height (H) for the retaining structure (for all angles ϴ) equals to 6 m and the most critical angle is ϴ= 45º to prevent the failure by tensile of tendon. While the bending failure reliability analysis shows that all heights of retaining structure are suitable. After comparing the two cases it was found that (G1) is more dangerous than (G2).

scholarly journals Experimental Analysis and Failure Criterion of Plain Concrete Subjected to Biaxial Loading under Fixed Lateral Loading

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Zhenpeng Yu ◽  
Xue Sun ◽  
Furong Li
Keyword(s):  
Principal Stress ◽  
Failure Criterion ◽  
Failure Modes ◽  
Biaxial Loading ◽  
Plain Concrete ◽  
Failure Criteria ◽  
Lateral Loading ◽  
Biaxial Compression ◽  
Proportional Loading ◽  
Stress Ratios

By using a rock true triaxial apparatus hydraulic servo machine, biaxial loading experiments including biaxial compression-compression and biaxial compression-tension with fixed lateral loading on plain concretes were conducted and the stress-strain curves of plain concrete under various stress ratios were obtained. After determining the peak principal stress, the damage modes of plain concrete under various stress ratios were analyzed and the law of strength in the principal stress direction was studied as well. The experimental findings show that, under the fixed lateral loading, the failure modes of plain concrete under biaxial compression-compression and biaxial compression-tension are very similar to those under the equal proportional loading, but with higher amplitude of variation. In this paper, Kupfer’s classical failure criterion was applied to verify the experimental data and the predicted biaxial loading on plain concrete under fixed lateral loading and was regarded as relatively conservative. Meantime, based on Kupfer’s failure criterion and octahedral stress space, two different failure criteria had been proposed and verified. The results show that the proposed failure criteria have good applicability. The failure mechanism under fixed lateral loading was discussed and compared with that under the equal proportional loading method. This research is meaningful to plain concrete engineering application and calculation.

AN ITERATIVE HDMR APPROACH FOR ENGINEERING RELIABILITY ANALYSIS

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Qian Wang
Keyword(s):  
Reliability Analysis ◽  
Probabilistic Analysis ◽  
Surrogate Models ◽  
Second Order ◽  
High Dimensional Model Representation ◽  
Performance Function ◽  
Reliability Indices ◽  
Reliability Method ◽  
Sample Points ◽  
A Performance

Engineering reliability analysis has long been an active research area. Surrogate models, or metamodels, are approximate models that can be created to replace implicit performance functions in the probabilistic analysis of engineering systems. Traditional 1st-order or second-order high dimensional model representation (HDMR) methods are shown to construct accurate surrogate models of response functions in an engineering reliability analysis. Although very efficient and easy to implement, 1st-order HDMR models may not be accurate, since the cross-effects of variables are neglected. Second-order HDMR models are more accurate; however they are more complicated to implement. Moreover, they require much more sample points, i.e., finite element (FE) simulations, if FE analyses are employed to compute values of a performance function. In this work, a new probabilistic analysis approach combining iterative HDMR and a first-order reliability method (FORM) is investigated. Once a performance function is replaced by a 1st-order HDMR model, an alternate FORM is applied. In order to include higher-order contributions, additional sample points are generated and HDMR models are updated, before FORM is reapplied. The analysis iteration continues until the reliability index converges. The novelty of the proposed iterative strategy is that it greatly improves the efficiency of the numerical algorithm. As numerical examples, two engineering problems are studied and reliability analyses are performed. Reliability indices are obtained within a few iterations, and they are found to have a good accuracy. The proposed method using iterative HDMR and FORM provides a useful tool for practical engineering applications.

Assessment of time-dependent reliability of reinforced concrete columns with uncertain load eccentricity

2000 ◽  
Vol 27 (3) ◽  
pp. 389-399
Author(s):  
H P Hong ◽  
W Zhou
Keyword(s):  
Reinforced Concrete ◽  
Reliability Analysis ◽  
Axial Load ◽  
Bending Moment ◽  
Time Dependent ◽  
Sensitivity Analyses ◽  
Live Load ◽  
Rc Columns ◽  
Reliability Indices ◽  
Reliability Method

An approach for the time-dependent reliability analysis of reinforced concrete (RC) columns considering the correlation between the axial load and the bending moment or the uncertainty in the load eccentricity is presented. The approach recursively uses the efficient first-order reliability method for the time-dependent reliability analysis. The proposed approach is more efficient than the ones used in the literature for the reliability analysis of RC columns. The proposed approach is used to carry out sensitivity analyses of the reliability of short RC columns to the time-dependent live load effects and to the correlation between the axial load and the bending moment. Results of the analyses suggest that the reliability of RC columns can be sensitive to the correlation between the axial load and the bending moment due to live load. The differences between the reliability indices obtained by considering the live load modeled as a pulse process and as an extreme variate can be large.Key words: reliability, load, time-dependent, time-independent, uncertainty, correlation, concrete, reinforcement, column.

scholarly journals RELIABILITY ANALYSIS OF A TWO SPAN FLOOR DESIGNED ACCORDING TO EUROCODE 5

2016 ◽  
Vol 36 (1) ◽  
pp. 18-25
Author(s):  
EN Ogork ◽  
AK Nakore
Keyword(s):  
Reliability Analysis ◽  
Structural Reliability ◽  
Load Ratio ◽  
Structural Safety ◽  
Live Load ◽  
Structural Elements ◽  
Limit States ◽  
Analysis And Design ◽  
Modes Of Failure ◽  
Reliability Method

This paper presents the structural reliability assessment of a two span timber floor of strength class D40 designed in accordance with Eurocode 5 (2004).  The Structural analysis and design of the timber floor system was carried out using deterministic approach, considering both ultimate and serviceability limit states. Reliability analysis of the floor structural elements to ascertain its level of safety was carried out using first order reliability method (FORM) for the four modes of failure of bending shear, bearing and deflection. The reliability analysis involved investigation of the effects of variation of the applied dead to live load ratio and the cross sectional parameters of the floor. The results revealed that the deterministic design is satisfactory as limiting stresses and deflection were not exceeded. The primary floor joists had safety indices in shear and bending of 1.2 to 2.8 with decrease in dead to live load ratio and were below the recommended safety index of 3.8 specified in joint committee on structural safety (JCSS). The timber floor structural elements are more reliable in bearing, shear and deflection and critical in bending mode of failure. The section depth and span of floor elements are more sensitive in bending and deflection modes than shear and bearing modes. http://dx.doi.org/10.4314/njt.v36i1.3

scholarly journals Probabilistic Assessment of Sandwiched Concrete Slabs in Deflection

2021 ◽  
Vol 9 (9) ◽  
pp. 2052-2058
Author(s):  
K. U. Unamba
Keyword(s):  
Reliability Analysis ◽  
Concrete Slab ◽  
Concrete Strength ◽  
Load Ratio ◽  
Concrete Slabs ◽  
Hollow Core ◽  
Probabilistic Evaluation ◽  
Eurocode 2 ◽  
Reliability Method ◽  
Design Requirements

Abstract: This study presents a probabilistic evaluation of concrete sand-witched hollow core slabs in accordance with the design requirements of BS8110 (1985; 1997) and Eurocode 2 (2008). The First Order Reliability Method (FORM) was used in computing the probability of failure. For the deflection failure, the effect of varying the load ratio and the breadth of slab on the reliability analysis were carried out at the following values of concrete strengths ݂ܿu: 25N/mm2 , 30 N/mm2 , 40 N/mm2 , 50 N/mm2 . The results indicate that deflection characteristics of the slab are directly affected by the concrete strength, loadings, breadth of slab selected. Thus, the deflection of the slab increases with increases in loading, hollow core, breadth of slab and decrease in concrete strength. This shows that the safety index of reinforced sandwiched concrete slab in deflection generally decreases as the load ratio and breadth of slab increase for each combination of concrete strength. Keywords: Probabilistic Analysis, Sandwiched Concrete, Reliability Analysis, Stochastic Model, FORM

First-Order Reliability Analysis of Vehicle Safety in Highway Horizontal Curves

2013 ◽  
Author(s):  
Jaekwan Shin ◽  
Ikjin Lee
Keyword(s):  
Reliability Analysis ◽  
Failure Modes ◽  
Design Method ◽  
First Order ◽  
Horizontal Curves ◽  
State Highway ◽  
Reliability Method ◽  
Current Design ◽  
Margin Of Safety ◽  
Analytic Models

This study presents a reliability analysis of vehicle sideslip and rollover in highway horizontal curves, mainly focusing on exit ramps and interchanges. To accurately describe failure modes of a ground vehicle, analytic models for sideslip and rollover are derived considering nonlinear characteristics of vehicle behavior using the commercial software, TruckSim®, with high fidelity. Then, the probability of accident is evaluated using the First-Order Reliability Method (FORM). Furthermore, sensitivity functions of each failure mode are analytically derived to apply FORM. Numerical studies are conducted using a single-unit truck model. The results show that a truck is more likely to rollover than to slip at dry load. To propose practical application of the study, the reliability analysis for the minimum radius recommended by American Association of State Highway and Transportation Officials (AASHTO) at various speeds and bank angles is conducted. The reliability analysis of current design method shows that the method cannot provide the sufficient margin of safety against both of rollover and sideslip when there are deviations from assumed conditions, especially at low speed of vehicles.

An Efficient Methodology for Fatigue Reliability Analysis of Mechanical Components Based on the Stress-Life Prediction Approach

2003 ◽  
Author(s):  
Jun Tang ◽  
Young Ho Park
Keyword(s):  
Fatigue Life ◽  
Reliability Analysis ◽  
Life Prediction ◽  
Failure Modes ◽  
Theoretical Background ◽  
Fatigue Reliability ◽  
Integrated Method ◽  
Reliability Method ◽  
Mechanical Components ◽  
Prediction Approach

An efficient methodology for fatigue reliability assessment and its corresponding fatigue life prediction of mechanical components using the First-Order Reliability Method (FORM) is developed in this paper. Using the proposed method, a family of reliability defined S-N curves, called R-S-N curves, can be constructed. In exploring the ability to predict spectral fatigue life and assessing the corresponding reliability under a specified dynamics environment, the theoretical background and the algorithm of a simple approach for reliability analysis will first be introduced based on fatigue failure modes of mechanical components. It will then be explained how this integrated method will carry out the spectral fatigue damage and failure reliability analysis. By using this proposed methodology, mechanical component fatigue reliability can be predicted according to different mission requirements.

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