A Multi-attribute Information Based Method of Material Strength Distribution Fitting

2020 ◽  
pp. 44-51
Author(s):  
Liyang Xie ◽  
Bo Qin ◽  
Ningxiang Wu
Keyword(s):  
Strength Distribution ◽  
Material Strength ◽  
Distribution Fitting ◽  
Attribute Information

A Renewal Weakest-Link Model of Strength Distribution of Polycrystalline Silicon MEMS Structures

2019 ◽  
Vol 86 (8) ◽  
Author(s):  
Zhifeng Xu ◽  
Roberto Ballarini ◽  
Jia-Liang Le
Keyword(s):  
Experimental Data ◽  
Polycrystalline Silicon ◽  
Microelectromechanical Systems ◽  
Strength Distribution ◽  
Material Strength ◽  
Mems Devices ◽  
Efficient Computation ◽  
Weakest Link ◽  
Large Size ◽  
The Stability

Experimental data have made it abundantly clear that the strength of polycrystalline silicon (poly-Si) microelectromechanical systems (MEMS) structures exhibits significant variability, which arises from the random distribution of the size and shape of sidewall defects created by the manufacturing process. Test data also indicated that the strength statistics of MEMS structures depends strongly on the structure size. Understanding the size effect on the strength distribution is of paramount importance if experimental data obtained using specimens of one size are to be used with confidence to predict the strength statistics of MEMS devices of other sizes. In this paper, we present a renewal weakest-link statistical model for the failure strength of poly-Si MEMS structures. The model takes into account the detailed statistical information of randomly distributed sidewall defects, including their geometry and spacing, in addition to the local random material strength. The large-size asymptotic behavior of the model is derived based on the stability postulate. Through the comparison with the measured strength distributions of MEMS specimens of different sizes, we show that the model is capable of capturing the size dependence of strength distribution. Based on the properties of simulated random stress field and random number of sidewall defects, a simplified method is developed for efficient computation of strength distribution of MEMS structures.

Some Principles of Brittle Material Design

1975 ◽  
Author(s):  
W. H. Dukes
Keyword(s):  
Statistical Methods ◽  
Stress Gradient ◽  
Statistical Treatment ◽  
Material Design ◽  
Strength Properties ◽  
Strength Distribution ◽  
Material Strength ◽  
Stress Distributions ◽  
Failure Loads ◽  
Actual Material

This paper presents the basic principles which must be followed in designing structures to utilize completely brittle materials to carry tensile loads or stresses in an efficient and reliable manner. Brittleness introduces a need for highly refined stress analysis methods. Brittleness also requires the statistical treatment of material strength because of sensitivity to microscopic flaws which are distributed statistically in size and shape. It proves, in fact, to be impractical to do this and still achieve the extremely low probabilities of failure expected of a primary structure. The use of statistical methods to describe the material strength properties should also be extended to the statistical treatment of loads applied to the component, because it is the overall probability of failure of the component which is significant. These methods must also be extended to cover such effects as nonuniform stress distributions, stress gradient and fatigue, and methods for doing this are suggested. Finally, the use of statistical methods raises problems in the verification of a design since the successful test of a small number of components is not likely to include material at the lower extremes of the strength distribution curve. The use of the proof test permits this problem to be circumvented by comparing component destruction test results with expected failure loads based on the actual material strength in each individual component.

Size Effect on Strength and Lifetime Distributions of Quasibrittle Structures

2009 ◽  
Author(s):  
Zdeneˇk P. Bazˇant ◽  
Jia-Liang Le
Keyword(s):  
Creep Crack Growth ◽  
Strength Distribution ◽  
Empirical Approach ◽  
Cumulative Distribution ◽  
Material Strength ◽  
Refined Theory ◽  
Engineering Structures ◽  
Atomic Lattice ◽  
Lifetime Distributions ◽  
The Mean

Engineering structures such as aircraft, bridges, dams, nuclear containments and ships, as well as computer circuits, chips and MEMS, should be designed for failure probability < 10−6–10−7 per lifetime. The safety factors required to ensure it are still determined empirically, even though they represent much larger and much more uncertain corrections to deterministic calculations than do the typical errors of modern computer analysis of structures. The empirical approach is sufficient for perfectly brittle and perfectly ductile structures since the cumulative distribution function (cdf) of random strength is known, making it possible to extrapolate to the tail from the mean and variance. However, the empirical approach does not apply to structures consisting of quasibrittle materials, which are brittle materials with inhomogeneities that are not negligible compared to structure size. This paper presents a refined theory on the strength distribution of quasibrittle structures, which is based on the fracture mechanics of nanocracks propagating by activation energy controlled small jumps through the atomic lattice and an analytical model for the multi-scale transition of strength statistics. Based on the power law for creep crack growth rate and the cdf of material strength, the lifetime distribution of quasibrittle structures under constant loads is derived. Both the strength and lifetime cdf’s are shown to be size- and geometry-dependent. The theory predicts intricate size effects on both the mean structural strength and lifetime, the latter being much stronger. The theory is shown to match the experimentally observed systematic deviations of strength and lifetime histograms of industrial ceramics from the Weibull distribution.

Experimental and Numerical Investigation on Manufacturing-Induced Material Inhomogeneity in Hydrogenation Reactor Shell

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Song Huang ◽  
You Li ◽  
Xinyi Song ◽  
Hu Hui ◽  
Jiru Zhong
Keyword(s):  
Load Capacity ◽  
Strength Distribution ◽  
Data Driven ◽  
Material Strength ◽  
Manufacturing Processes ◽  
Material Inhomogeneity ◽  
Actual Material ◽  
Hydrogenation Reactor ◽  
Good Agreement

Abstract Hydrogenation reactor services as key equipment in chemical and energy industries. Manufacturing processes of hydrogenation reactor changes its performance before long-term service but impact of manufacturing residual influence remains unclear. In this work, actual material strength distribution (MSD) in hydrogenation reactor shell was investigated. First, a hydrogenation reactor shell made from 2.25Cr1Mo0.25V was dissected to measure MSD in thickness. Then, a numerical model was proposed to predict actual material strength in hydrogenation reactor shell. The model employs both data-driven and finite element techniques to simulate material evolution during manufacturing. Third, the predict results were discussed with respect to accuracy based on experiment result. Results exhibit good agreement between predicted value and experiment outcomes. At last, impact of manufacturing residual influence on load capacity of hydrogenation reactor shell was investigated. Results indicate that fit for service (FFS) evaluation of hydrogenation reactor based on heat treatment material properties is not conservative. This work will contribute to the accurate description of hydrogenation reactor's performance.

scholarly journals Development of Ceramic Hot Section Components for AGT 100 Gas Turbine

1987 ◽  
Author(s):  
D. A. Turner ◽  
R. L. Holtman
Keyword(s):  
Probabilistic Approach ◽  
Ceramic Materials ◽  
Strength Distribution ◽  
Material Strength ◽  
Design Development ◽  
Component Reliability ◽  
Probability Of Survival ◽  
2D Simulation ◽  
Component Test ◽  
Engine Testing

The development of the AGT 100 gasifier turbine components in structural ceramic materials is described. Development is defined as the complete and iterative cycle from design, analysis, test, and design refinement culminating in successful demonstration of the design requirements. The components are analyzed by a linear elastic probabilistic approach, which involves finite element (3D and/or 2D) simulation of the component combined with a Weibull characterization of the brittle ceramic material strength distribution to calculate a probability of survival for the component in the operating environment. Component test failure investigation has resulted in design modifications, and an improvement in component reliability has been demonstrated. Engine testing (five hundred plus hr to date) continues to assess design/development of structural ceramics.

Analisis Daya Dukung Tanah Dan Bahan Pondasi Tiang Pancang Pada Pembangunan Jembatan Kab. Jombang

2020 ◽  
Vol 9 (1) ◽  
pp. 32-37
Author(s):  
Ruslan Hidayat ◽  
Saiful Arfaah
Keyword(s):  
Carrying Capacity ◽  
Pile Foundation ◽  
Heavy Traffic ◽  
Traffic Volume ◽  
Material Strength ◽  
Cone Penetrometer ◽  
The Village

One of the most important factors in the structure of the pile foundation in the construction of the bridge is the carrying capacity of the soil so as not to collapse. Construction of a bridge in the village of Klitik in Jombang Regency to be built due to heavy traffic volume. The foundation plan to be used is a pile foundation with a diameter of 50 cm, the problem is what is the value of carrying capacity of soil and material. The equipment used is the Dutch Cone Penetrometer with a capacity of 2.50 tons with an Adhesion Jacket Cone. The detailed specifications of this sondir are as follows: Area conus 10 cm², piston area 10 cm², coat area 100 cm², as for the results obtained The carrying capacity of the soil is 60.00 tons for a diameter of 30 cm, 81,667 tons for a diameter of 35 cm, 106,667 tons for a diameter of 40 cm, 150,000 tons for a diameter of 50 cm for material strength of 54,00 tons for a diameter of 30 cm, 73,500 tons for a diameter of 35 cm, 96,00 tons for a diameter of 40 cm, 166,666 tons for a diameter of 50 cm

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