A Procedure for Drop-Tower Testing of Shallow-Cracked, Single-Edge Notched Bend Specimens

2009 ◽  
pp. 50-50-26 ◽  
Author(s):  
MT Kirk ◽  
JP Waskey ◽  
RH Dodds
Keyword(s):  
Drop Tower ◽  
Single Edge

scholarly journals Spectral Gap of the Largest Eigenvalue of the Normalized Graph Laplacian

2021 ◽  
Author(s):  
Jürgen Jost ◽  
Raffaella Mulas ◽  
Florentin Münch
Keyword(s):  
Lower Bound ◽  
Bipartite Graph ◽  
Spectral Gap ◽  
Complete Bipartite Graph ◽  
Graph Laplacian ◽  
New Method ◽  
Single Edge ◽  
Largest Eigenvalue ◽  
Complement Graph ◽  
The Largest Eigenvalue

AbstractWe offer a new method for proving that the maxima eigenvalue of the normalized graph Laplacian of a graph with n vertices is at least $$\frac{n+1}{n-1}$$ n + 1 n - 1 provided the graph is not complete and that equality is attained if and only if the complement graph is a single edge or a complete bipartite graph with both parts of size $$\frac{n-1}{2}$$ n - 1 2 . With the same method, we also prove a new lower bound to the largest eigenvalue in terms of the minimum vertex degree, provided this is at most $$\frac{n-1}{2}$$ n - 1 2 .

scholarly journals Modelling the Variability and the Anisotropic Behaviour of Crack Growth in SLM Ti-6Al-4V

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1400
Author(s):  
Rhys Jones ◽  
Calvin Rans ◽  
Athanasios P. Iliopoulos ◽  
John G. Michopoulos ◽  
Nam Phan ◽  
...  
Keyword(s):  
Crack Growth ◽  
The United States ◽  
Fatigue Threshold ◽  
Growth Equation ◽  
Single Edge ◽  
Test Program ◽  
Large Variability ◽  
Single Edge Notch ◽  
Anisotropic Behaviour ◽  
Edge Notch

The United States Air Force (USAF) Guidelines for the Durability and Damage Tolerance (DADT) certification of Additive Manufactured (AM) parts states that the most difficult challenge for the certification of an AM part is to establish an accurate prediction of its DADT. How to address this challenge is the focus of the present paper. To this end this paper examines the variability in crack growth in tests on additively manufactured (AM) Ti-6Al-4V specimens built using selective layer melting (SLM). One series of tests analysed involves thirty single edge notch tension specimens with five build orientations and two different post heat treatments. The other test program analysed involved ASTM standard single edge notch specimens with three different build directions. The results of this study highlight the ability of the Hartman–Schijve crack growth equation to capture the variability and the anisotropic behaviour of crack growth in SLM Ti-6Al-4V. It is thus shown that, despite the large variability in crack growth, the intrinsic crack growth equation remains unchanged and that the variability and the anisotropic nature of crack growth in this test program is captured by allowing for changes in both the fatigue threshold and the cyclic fracture toughness.

Tiered Sampling

2021 ◽  
Vol 15 (5) ◽  
pp. 1-52
Author(s):  
Lorenzo De Stefani ◽  
Erisa Terolli ◽  
Eli Upfal
Keyword(s):  
Large Scale ◽  
Analysis Of Algorithms ◽  
Base Layer ◽  
Single Edge ◽  
Real World Data ◽  
High Quality ◽  
Large Graphs ◽  
Massive Graphs ◽  
Variance Estimate ◽  
Low Probability

We introduce Tiered Sampling , a novel technique for estimating the count of sparse motifs in massive graphs whose edges are observed in a stream. Our technique requires only a single pass on the data and uses a memory of fixed size M , which can be magnitudes smaller than the number of edges. Our methods address the challenging task of counting sparse motifs—sub-graph patterns—that have a low probability of appearing in a sample of M edges in the graph, which is the maximum amount of data available to the algorithms in each step. To obtain an unbiased and low variance estimate of the count, we partition the available memory into tiers (layers) of reservoir samples. While the base layer is a standard reservoir sample of edges, other layers are reservoir samples of sub-structures of the desired motif. By storing more frequent sub-structures of the motif, we increase the probability of detecting an occurrence of the sparse motif we are counting, thus decreasing the variance and error of the estimate. While we focus on the designing and analysis of algorithms for counting 4-cliques, we present a method which allows generalizing Tiered Sampling to obtain high-quality estimates for the number of occurrence of any sub-graph of interest, while reducing the analysis effort due to specific properties of the pattern of interest. We present a complete analytical analysis and extensive experimental evaluation of our proposed method using both synthetic and real-world data. Our results demonstrate the advantage of our method in obtaining high-quality approximations for the number of 4 and 5-cliques for large graphs using a very limited amount of memory, significantly outperforming the single edge sample approach for counting sparse motifs in large scale graphs.

Stress concentration of a strip with a single edge notch

1987 ◽  
Vol 28 (2) ◽  
pp. 223-238 ◽  
Author(s):  
Noda Nao-Aki ◽  
Nisitani Hironobu
Keyword(s):  
Stress Concentration ◽  
Single Edge ◽  
Single Edge Notch ◽  
Edge Notch

Numerical fracture investigation of single-edge notched asphalt concrete beam based on random heterogeneous FEM model

2021 ◽  
Vol 304 ◽  
pp. 124581
Author(s):  
Guocui Teng ◽  
Chuanfeng Zheng ◽  
Xiangyin Chen ◽  
Xuli Lan ◽  
Yimo Zhu ◽  
...  
Keyword(s):  
Asphalt Concrete ◽  
Concrete Beam ◽  
Single Edge ◽  
Fem Model

scholarly journals The Drop Tower Bremen

2010 ◽  
Vol 22 (4) ◽  
pp. 461-461 ◽  
Author(s):  
M. Dreyer
Keyword(s):  
Drop Tower

Comparative Analysis of Fracture Toughness Obtained by Different Techniques in Alumina Matrix - Dispersed TZP Zirconia Composites

2016 ◽  
Vol 869 ◽  
pp. 46-51
Author(s):  
Daniel Alessander Nono ◽  
Eron Fernandes da Silva ◽  
Maria do Carmo de Andrade Nono ◽  
Francisco Piorino Neto ◽  
Sergio Luiz Mineiro
Keyword(s):  
Fracture Toughness ◽  
Tetragonal Zirconia ◽  
Ceramic Composites ◽  
Alumina Matrix ◽  
Single Edge ◽  
Chemical Inertness ◽  
Edge Notch ◽  
Properties Of Materials ◽  
Experimental Values ◽  
Benefit Cost

The fracture toughness is one of the requirements for mechanical properties of materials for use in satellites. The ceramic TZP zirconia (tetragonal zirconia polycrystals) have been investigated for applications in ballistic armor. Due to the chemical inertness and fracture toughness, this material has the potential to act as a screen against impacts of micrometeorites and space debris. The ceramic composites of alumina-zirconia 3Y-TZP (tetragonal zirconia polycrystals doped with 3 mol% ytria ) are the materials with the best benefit / cost for this application. This paper presents and discusses the results obtained from the use of two techniques for determining fracture toughness. The composite alumina - 18.5% of 3Y-TZP zirconia nanoparticles obtained from deflocculated powders have been tested for Vickers and the SEVNB penetration method (Single-Edge-Notch Beam V) to obtain the fracture toughness values (KIC). The KIC values obtained were analyzed due to the lower dispersion of experimental values. The SEVNB method showed better reliability in determining the toughness values in the studied ceramics.

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