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Evaluation of the torsion test for determining the shear strength of structural lumberHeck, Leanne Renee 06 November 1997 (has links)
The torsion test was evaluated as a method for determining the shear
strength of full-size structural lumber. The evaluation involved an experimental
length study, an experimental depth study, and a finite element study.
The length study consisted of fifty nominal 2x4 specimens, ten specimens
for each length, and ten American Society for Testing and Materials (ASTM)
shear blocks. One 14 foot long board yielded one specimen for each length: (a)
21.0", (b) 28.5", (c) 32.0", (d) 35.5", (e) 39.0", and (f) an ASTM D143-94 shear
block. The statistical analysis revealed no evidence that the length affected the
shear strength.
The depth study consisted of fifty specimens, ten specimens for each
depth: (a) 2x4, (b) 2x6, (c) 2x8, (d) 2x10, and (e) 2x12. In addition, fifty ASTM
shear blocks, one block for each specimen, were tested. The statistical study did not reveal convincing evidence of a depth effect on shear strength, even
after accounting for specific gravity and shear span as covariates.
Failure modes for the torsion samples involved a longitudinal shear crack
at the mid-point of the longest side, which propagated toward the ends of the
specimen and through the cross section perpendicular to the growth rings.
The finite element model revealed that uniform shear stress occurs within
the shear span, which begins and ends a distance of approximately two times
the depth plus the grip distance away from each end of the member. In addition,
torsion theory verified that the experimental shear failure plane that occurs
within the shear span is parallel to the grain and the shear slippage is also
parallel to the grain, similar to the known shear failure in specimens subjected to
bending loads.
Based on the results of this study, the torsion test is the best practical
method to determine the pure shear strength of full-size structural lumber,
because the test yields 100% shear failures and the specimen is in a state of
pure shear stress. / Graduation date: 1998
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Development of performance based test procedures for asphalt mixturesKliewer, Julie E. 13 December 1994 (has links)
In 1987, Congress authorized a 5 year $150 million dollar research program called
the Strategic Highway Research Program (SHRP). SHRP was divided into four major
areas, including the asphalt research program. The asphalt research program was divided
into six major research contracts, one such contract, SHRP-003A was called Performance
Related Testing and Measuring of Asphalt Aggregate Interaction and Mixtures. Oregon
State University performed the portion of this contract related to the development and
validation of accelerated test procedures for aging, low temperature cracking, and
moisture sensitivity of asphalt-aggreagte mixtures. This thesis contains five independent
papers that discuss elements of the development, validation, and or implementation of
these accelerated test procedures.
In the first paper, the relationship between field performance and laboratory aging
properties of asphalt-aggregate mixtures is discussed, including the relative importance of
asphalt binder and aggregate type on the amount of aging experience. Based on this work
recommended aging procedures are presented to simulate different environmental
conditions and pavement age.
The second paper makes use of the large body of resilient modulus data conducted
as part of the SHRP research effort to compare data obtain in the diametral and the
triaxial mode. It is not possible to give a relationship between triaxial and diametral
resilient modulus, without describing specimen geometry and other test conditions.
The third paper discusses the effect of aging on the thermal cracking properties of
asphalt-aggregate mixtures. The temperature at which aging occurs affects the way cold
temperature fracture properties change with time. Low temperatures result in quenching
of the aging process, while high temperatures result in continued aging.
The fourth paper discusses work conducted in association with the Oregon
Department of Transportation to extend the environmental conditioning system (ECS)
test procedure for moisture assessment to open graded mixtures. Comparison in the ECS
of mixtures with and without anti-strip agents added indicates that they don't always
decrease moisture damage potential.
The final paper presents a discussion of asphalt chemistry and its relationship to
asphalt-aggregate mixture performance. Using the SHRP asphalt model, aging and low
temperature performance data collected at Oregon State University is explained. / Graduation date: 1995
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Ultralite copper reflex tube life test and ceramic fabric wicking rate experimentsSnuggerud, Ross D. 22 January 1993 (has links)
This thesis covers two topics. The first subject
involves tests run on a ultralite reflux tube supplied by
Battelle Pacific Northwest Laboratories (PNL). The second
topic involves tests to determine the relative wicking rates
of several different fabrics.
The ultralite reflux tube supplied by PNL was
constructed of copper and Nextel 312. It had a 10 mil thick
copper evaporator and a 10 mil thick copper condenser end
cap. The bulk of the condenser was 2 mil thick copper
covered by a one inch diameter Nextel 312 woven hose. A
life test was run within the Heat Pipe Test Facility, a
chamber used to simulate low earth orbit. The life test
lasted for over 800 hours, during which time the reflux tube
operated steadily with no drop in performance. At the end
of the test the reflux tube was removed and observed. The
only noticeable change was a slight discoloration of the
Nextel 312 used to cover the condenser. This discoloration
was consistent with previously observed phenomenon.
The second topic, fabric wicking rate studies were done
as a follow up study to the dry uptake tests previously
conducted at Oregon State University. The purpose of the
tests were to get a relative feel for the ability of
different fabrics to wick water. This was achieved using a
drop test in which the fabrics were laid out on a bridge
connecting two containers. One of the containers was
elevated above the other. The fabrics were allowed to wick
water from the upper container to the lower container and
the rate at which this was accomplished was measured. The
fabrics were all able to move significant amounts of water.
The stiffer fabrics seemed to perform better. The major
transport mechanism was transport between fabric layers and
the fabric and the bridge. / Graduation date: 1993
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Effectiveness comparison between Concolic and Random TestingLai, Yan-shun 31 October 2011 (has links)
The development of software today, the company has their own test system usually. Because there has a few bugs in the every software. And it will make the damage of company¡¦s property or security of information. We can find the bugs in the software by the test systems. But the few bugs will appear repeatedly even if you have been fixed it. In this time, it will be effective if we use the automatic test systems. They can solve the waste of time and cost.
Appearance of the automatic test system has been solved the defect of the test method in the past. In this paper will mention two kind of automatic test systems, one of them is concolic testing, and another is random testing. In the 2009, there had the few of evidence to discuss that the concolic testing was more effective than the random testing, but there wasn¡¦t have the enough demonstration. So I hope to prove that the effectiveness comparison between concolic and random testing by this paper.
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A New Combinatorial Strategy to Black-box Testing with ConstraintsTsai, Tsung-Han 23 July 2007 (has links)
In recent year, a lot of scholar try to generate test sets for combinatorial strategy automatically. But these algorithms based on combinatorial strategy don¡¦t consider conflicts of input parameter model. A conflict exists when the result of combining two
or more values of different parameter dose not make sense. Thus, invalid sub-combinations may be included in test cases in the test suite, and these are useless to us. Besides, these algorithms all directly generate all test cases once, in other words,
it is unable to utilize test cases generated at present to feedback and revise the algorithm, so it is easy to generate useless combinations.
So, this paper proposes new test generation algorithm for combinatorial testing based on constraint satisfaction problem(CSP) to solve problem which invalid sub-combinations may be included in test cases, and we can add constraints flexibly during generating test cases to avoid generate useless or repeated combinations. The experimental result indicate that our algorithm perform well, with respect to the amount of time required for test generation, otherwise, we can generate conflict-free
test cases directly.
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A Flexible Combinatorial Strategy based on Constraint Statisfaction ProblemLi, Cheng-Hsuan 23 August 2009 (has links)
In recent year the research field of the combinatorial testing, which can roughlybe divided into two kinds including pair-wise coverage and multi-wise coverage. a lot of scholar try to use various strategies to generate test data automatically. In order to weight the generated test set, the generated test data must satisfy certain criterion. But these combinatorial strategy neglected the flexibility of using on the practice.
Considering software testing from the practice, which often be restricted by the cost. For this reason, how to obtaint the greatest testing benefits under the limited cost must be considered on the parctice. But in the extant combinatorial strategy, there is no flexible use. In other words, we must testing test set totally. Therefore, there is very great restriction to exist on using the test data generated by the extant combinatorial strategy on the practice.
So, this paper proposes a flexible combinatorial strategy based on CSP, which allow users to do the most valid testing under the limited cost, which also allow users join the constraints that needs at any time during the testing process, revise the test data that we produced dynamically. The experimental result indicate that our method perform well, it can avoid including the test data whether some users think the interests less or unnecessarier, in order to achive the greatest testing beneifts.Further, we can achive the goal of reducing the quantity of testing data.
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DUNE SAND-AGGREGATE MIXES AND DUNE SAND-SULFUR MIXES FOR ASPHALTIC CONCRETE PAVEMENTSFatani, Mohamed Noor Yaseen, 1944- January 1980 (has links)
No description available.
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Structure-process-property relationships in polyester spun yarns : the role of fiber frictionHong, Joohyun 12 1900 (has links)
No description available.
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Composites at micro- and nano-scale and a new approach to the problem of a concentrated force on a half-planeJordan, Jeff 05 1900 (has links)
No description available.
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Short- and long-term behavior of axially compressed slender doubly symmetric fiber-reinforced polymeric composite membersScott, David William 08 1900 (has links)
No description available.
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