scholarly journals An experimental approach to evaluate the role of rock failure modes in mechanical characterization of metabasalts

2021 ◽  
Author(s):  
Sreyashi Bhowmick ◽  
Bikash Kumar Ram ◽  
Tridib Kumar Mondal
Keyword(s):  
Failure Mode ◽  
Triple Junction ◽  
Failure Modes ◽  
Mechanical Characterization ◽  
Point Load ◽  
Rock Failure ◽  
Load Test ◽  
Single Plane ◽  
Testing Conditions

Abstract A detailed understanding on rock failure modes testifies the competence of support designs for engineering work. Studying such failure modes using physical models of rock samples under laboratory conditions can be time efficient, informative and economically viable. In this study, the mechanical behavior of massive metabasalts were characterized with reference to rock failure modes through index tests such as point load and Brazilian testing conditions. Rock failure modes under point load test are categorized as i) single plane failure mode, ii) triple junction failure mode, iii) twisted failure mode and iv) single plane (inclined). It is observed that twisted and triple junction failure modes are observed for the samples with higher point load strength values (> 6 MPa). A total of five types of rock failure modes were observed in metabasalts under Brazilian testing conditions such as i) central multiple, ii) central, iii) non-central, iv) central multiple + layer activation and v) conjugate failure modes. Central multiple failure mode is found to be the most common failure mode in metabasalts due to its massive nature. It is also observed that all failure modes under Brazilian test are transpired in the range of 8 to 12 MPa. Among all other perceived rock failure modes, single plane (inclined) and conjugate failure modes under point load and Brazilian tests respectively are introduced in this study. It is evident that rock failure modes, which lead to control the strength of the rocks, should be considered as an important aspect for mechanical characterization of rock materials.

Case Study and Fault Modeling for Wrong Redundancy Evaluation on DRAM Devices

2007 ◽  
Author(s):  
Martin Versen ◽  
Dorina Diaconescu ◽  
Jerome Touzel
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Fault Modeling ◽  
Mode Analysis ◽  
Root Cause ◽  
Failure Mode Analysis

Abstract The characterization of failure modes of DRAM is often straight forward if array related hard failures with specific addresses for localization are concerned. The paper presents a case study of a bitline oriented failure mode connected to a redundancy evaluation in the DRAM periphery. The failure mode analysis and fault modeling focus both on the root-cause and on the test aspects of the problem.

scholarly journals Characterization of Weathered Soft Rock Mass by Index Tests

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Fernandes Leão M
Keyword(s):  
Rock Mass ◽  
Soft Rock ◽  
Point Load ◽  
Load Test ◽  
Rock Properties ◽  
Morphological Description ◽  
Durability Test ◽  
Stability Issues ◽  
Weathering Zone

The understanding of geotechnical and geomechanical rock mass behavior is challenging, mainly regarding weathered parts, since they may trigger stability issues. Soft Rocks, as phyllite, are known to enhance these problems. In this case, a road cut on a highway between the cities of Ouro Preto and Mariana (MG – Brazil) was studied, showing a particular weathering zone with changing conditions. After morphological description and geological fragmentation (using geological hammer, the Schmidt hammer and a switchblade) of the weathering zone, tests were done on rock matrix and rock mass in order to identify the discontinuity features. Physical properties were determined by physical index, using the point load test and slake durability test. The results permit to define the weathering zone, showing some huge anisotropy and heterogeneity in the rock properties.

Investigation on the Flexural Behaviour of Steel Cold Formed Built Up Sections

2020 ◽  
Vol 12 (9) ◽  
Author(s):  
T. Preethi ◽  
◽  
P. R. Kannan Rajkumar ◽  
M. Jegan ◽  
◽  
...  
Keyword(s):  
Failure Modes ◽  
Point Load ◽  
Load Test ◽  
Experimental Investigations ◽  
Ansys Software ◽  
Flexural Behaviour ◽  
Analytical Analysis ◽  
Corrugated Webs ◽  
Substantial Progress ◽  
Made In

For the past few decades, substantial progress has been made in material properties and construction methodology, which demands in need of development of stronger and lighter members in structural steel applications. The demands of increase in strength and reduction in weight of sections leads to development of structures which are slender and also stability plays a major role in design. The main goal of this study is to develop and investigate the performance of build-up steel I beam sections with corrugated webs. This study focuses on analysis of flexural behaviour and failure modes of plain web, rectangular, trapezoidal web and triangular web in beams by experimental investigations using three-point load test and analytical investigations using ANSYS software. From experimental and analytical analysis, triangular corrugated web beam performs better compared to all section. The experimental results obtained are more similar to analytical results obtained by ANSYS software with only slight deviations. The failure modes in both experimental investigation and analytical analysis are similar.

The Application of Getting Rc Value from Point Load Test and Rebound Test by Tunnel Surrounding Rock Classification System

2014 ◽  
Vol 580-583 ◽  
pp. 1116-1121 ◽  
Author(s):  
Ri Xu Wang ◽  
Zhong Chen Yuan
Keyword(s):  
Classification System ◽  
Point Load ◽  
Surrounding Rock ◽  
Load Test ◽  
High Status ◽  
Rock Classification ◽  
Point Load Test ◽  
User Friendly ◽  
Quantitative Indicators

The point load test and rebound tests were part of a simple rock testing methods, which together with a user-friendly, work environment characterized by less demanding test, so test the application of rock in the tunnel are very broad. Obtained by these two tests of rock uniaxial compressive strength Rc saturation level for the characterization of rock hard quantitative indicators, in the rock classification has a high status. With the computer technology in tunnel works in the field of application that can batch test data to establish the tunnel surrounding rock classification system. Article is based on two kinds of test in the same tunnel project in contrast to the use, through the rock classification system to analyze and evaluate both.

scholarly journals Characterization of Adobe Blocks: Point-Load Assessment as a Complementary Study of Damaged Buildings and Samples

Heritage ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 864-888
Author(s):  
Adria Sanchez-Calvillo ◽  
Elia M. Alonso-Guzman ◽  
Wilfrido Martinez-Molina ◽  
Marco A. Navarrete-Seras ◽  
Jose L. Ruvalcaba-Sil ◽  
...  
Keyword(s):  
Rural Communities ◽  
Formal Analysis ◽  
Complete Characterization ◽  
Point Load ◽  
Load Test ◽  
Construction Technique ◽  
Load Tests ◽  
Non Destructive

Adobe masonry is one of the oldest construction systems still in use today, Mexico has an enormous cultural heritage with traditional adobe houses being very representative of the rural communities and their culture. The 2017 Puebla Earthquake on September 19th struck the country causing the loss, destruction, and damage of historic buildings in several Mexican states, with the traditional earthen dwellings being the most vulnerable structures to these events. The fast abandonment of the local materials and techniques entails further research regarding the characterization of these construction systems, therefore, reconstruction efforts first require the recovery of the construction technique. After the seismic events, adobe samples of the remaining adobe structures of Jojutla de Juarez were collected. This population was one of the most affected in all the country, and, because of the major losses suffered, the study was conducted to determine the material properties of the dwellings’ adobe shards and natural quarry clays of the region. The characterization included destructive and non-destructive tests, mineralogical and granulometry analyses, and composition of the adobe samples of the buildings, as well as the aggregates. As a novelty, the compressive strength of the pieces was tested by two methods: the traditional compression strength test and the point-load test, in order to obtain the indicative values and the correlation equations between both tests. From the formal analysis and the laboratory, it was observed that the adobes from Jojutla presented different compositions which combined with the building malpractices and alterations to the traditional systems caused unpredictable behavior during the earthquake. The conduction of point-load tests in situ, as a part of a complete characterization methodology, could be an alternative to study the mechanical properties of patrimonial or damaged building samples before its disappearance.

scholarly journals Indirect test methods for the mechanical characterization of building stones

2018 ◽  
Vol 192 ◽  
pp. 01019
Author(s):  
Giulia Forestieri
Keyword(s):  
Southern Italy ◽  
Mechanical Characterization ◽  
Test Methods ◽  
Point Load ◽  
Building Stones ◽  
Indirect Test ◽  
Schmidt Hammer ◽  
Indirect Methods ◽  
Ucs Test

The main objective of this study is to evaluate the usefulness of indirect methods to estimate the uniaxial compressive strength (UCS) of building stones. For this purpose, the results of the UCS test on five types of stones from southern Italy, one igneous and four sedimentary stones are firstly correlated with the corresponding results from Schmidt hammer, point load and UCS direct tests. Then, derived correlations are compared with the equations obtained by different researchers in the mechanical stone characterization.

Ferrule Design Does Not Affect the Biomechanical Behavior of Anterior Teeth Under Mechanical Fatigue: An In Vitro Evaluation

2019 ◽  
Vol 44 (3) ◽  
pp. 273-280 ◽  
Author(s):  
FE Figueiredo ◽  
RC Santos ◽  
AS Silva ◽  
AD Valdívia ◽  
LA Oliveira-Neto ◽  
...  
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Load Test ◽  
Rank Test ◽  
Fiber Post ◽  
Root Fracture ◽  
Anterior Teeth ◽  
Log Rank Test ◽  
Significant Difference ◽  
Group A

SUMMARY Objectives: To investigate the survival and failure mode of fiber-post resin restorations over preparations with different ferrule designs when submitted to a fatigue load test. Methods and Materials: Fifty bovine incisors were selected and divided into five groups (n=10) according to ferrule design: a no-ferrule group, a 2-mm circumferential ferrule group, a 2-mm buccal ferrule group, a 2-mm lingual ferrule group, and a 2-mm buccal and lingual ferrule group. The fiberglass post was cemented and the composite core was built up and prepared, followed by cementation of a full composite crown. The samples were subjected to a cyclic fatigue test with loading applicator at 135°; a staircase approach was used until fracture. Survival (cycles to fracture) and failure modes were recorded. Survival data were analyzed with the log-rank test, while Kruskal-Wallis and Fisher exact tests were used to analyze failure mode data (α=0.05). Results: The median number of cycles to fracture ranged from 215,000 to 236,153. The log-rank test showed no statistically significant difference in survival rates among the groups (p=0.82). Regarding failure mode, three types were observed: I, post and/or core fracture; II, root fracture in the cervical third; and III, root fracture in the middle third. No statistical difference was observed among the groups (Kruskal-Wallis test, p=0.147). Conclusion: The ferrule design had no effect on fatigue resistance or failure mode of endodontically treated incisor teeth restored with a fiber post, composite core buildup, and composite crown.

scholarly journals Behaviour of Reinforced Concrete Beams With Circular Transverse Openings Under Static Loads

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Ling Jen Hua ◽  
Howe Sheng Tang ◽  
Wen Kam Leong ◽  
How Teck Sia
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Equation Model ◽  
Point Load ◽  
Load Test ◽  
Reinforced Concrete Beams ◽  
Structural Behaviour ◽  
Beam Height

Transverse opening in a reinforced concrete beam allows the crossing of mechanical and electrical services through the beam. However, it affects the strength of a beam. Understanding its structural behaviour is crucial to ensure a safe design of the beam. For that, an experimental study was carried out on reinforced concrete beams with circular transverse openings. The four-point load test was conducted to study the effects of the size and the position of the opening on the beam performance under the shear and flexural loads. In addition, three reinforcing methods for the opening were tested. The beams were evaluated in terms of the load-displacement responses, mechanical properties, deflections, and failure modes. The opening with the diameter not exceeding 0.25 times beam height affected about 20% of beam strength (without reinforcements at the opening). The diagonal bar reinforcing method effectively restored the beam strength for the opening size not exceeding 1/3 of beam height. The equation model proposed conservatively predicted the ultimate capacity of the beam with a transverse opening.

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