Laboratory Simulation of Structural Fatigue Behavior

2009 ◽  
pp. 74-74-18 ◽  
Author(s):  
J Morrow ◽  
RM Wetzel ◽  
TH Topper
Keyword(s):  
Fatigue Behavior ◽  
Laboratory Simulation ◽  
Structural Fatigue

Thermomechanical Fatigue Behavior of NiTi Wires

2013 ◽  
Vol 738-739 ◽  
pp. 311-315
Author(s):  
Antonio Isalgué ◽  
Javier Fernández ◽  
Nuria Cinca ◽  
I.G. Cano ◽  
Ramón Grau ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Smart Materials ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Constant Load ◽  
Niti Wire ◽  
Structural Fatigue ◽  
Mechanical Cycling ◽  
Thermal Actuation ◽  
Niti Wires

Applications of the functional, smart materials SMA need a careful evaluation of the working conditions and fatigue life. Structural fatigue failure in NiTi usually comes from a surface defect inducing crack growth, and this means that fatigue has to be studied for concrete applications, with the correct samples, as the state of the material presents size effects. Testing machine experiments on Ni-rich pseudoelastic wires indicate that the main parameter controlling the fatigue life in the traction-traction experiments is the effective stress on the NiTi wire. Long wire life (in the million cycle regime) can be achieved under limited stresses (under 170 MPa) in traction-traction tests. Also, experiments have been done on thermal actuation of NiTi wire under traction at constant load. Long actuator life (larger than 400000 cycles) can be achieved at low stresses (around 100 MPa), coherently with the results from the mechanical cycling.

Laboratory Simulation of Lunar Luminescence

1962 ◽  
Vol 14 ◽  
pp. 441-444 ◽  
Author(s):  
J. E. Geake ◽  
H. Lipson ◽  
M. D. Lumb
Keyword(s):  
Science And Technology ◽  
Laboratory Simulation ◽  
The Moon ◽  
Physics Department ◽  
Luminescent Spectrum

Work has recently begun in the Physics Department of the Manchester College of Science and Technology on an attempt to simulate lunar luminescence in the laboratory. This programme is running parallel with that of our colleagues in the Manchester University Astronomy Department, who are making observations of the luminescent spectrum of the Moon itself. Our instruments are as yet only partly completed, but we will describe briefly what they are to consist of, in the hope that we may benefit from the comments of others in the same field, and arrange to co-ordinate our work with theirs.

THE FATIGUE BEHAVIOR OF FRESHWATER ICE

1987 ◽  
Vol 48 (C1) ◽  
pp. C1-329-C1-335 ◽  
Author(s):  
W. A. NIXON ◽  
R. A. SMITH
Keyword(s):  
Fatigue Behavior ◽  
Freshwater Ice

EVALUASI PROGRAM PEMODELAN DAN SIMULASI LABORATORIUM KIMIA PADA MAHASISWA CALON GURU

EDUSAINS ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 201-211
Author(s):  
Yenni Kurniawati ◽  
Yuni Fatisa
Keyword(s):  
Mixed Method ◽  
Random Sampling ◽  
Sample Selection ◽  
Product Evaluation ◽  
Thinking Skills ◽  
Laboratory Simulation ◽  
Input Process ◽  
Improvement Program ◽  
Chemistry Students ◽  
Process Product

Abstract Modeling and laboratory simulation can help overcome of cost obstacle, time, safety and other constraints in laboratory experiments. Many skills also had the opportunity to be fostered and promoted, especially in connection with the construction of thinking skills. However, the implementation of this program required an evaluation, in order to decided whether the program will be continuing or not, in addition its needed to found the focused of on overall quality of learning in order to make a recommendation in the decision making. This research was conducted by the mixed-method approached with triangulation design, in order to evaluate the effectiveness, problems or any obstacles of the implementation of the program. The population in this study was the third semester of pre-service chemistry students at UIN Syarif Kasim Sultan Riau, which was supported by lecturers, assistant laboratory and staf. The sample selection was done using random sampling techniques. Program evaluation in this study was conducted by the CIPP model (Context, Input, Process, Product). The results showed that the program was running quite effective when viewed from the overall average grades. The evaluation about context, inputs, processes and products had the good and very good score, in which the evaluation score of context and input, get the better score than process and product evaluation. This study recommends to be a continuing improvement program of modeling and simulation laboratories, both as an exercise before the experiments or replace the real experiments. Keywords: modeling; simulation lab; chemistry experiment Abstrak Pemodelan dan simulasi laboratorium dapat membantu mengatasi kendala biaya, waktu, alasan keselamatan dan kendala lainnya dalam praktikum di laboratorium kimia. Beragam kemampuan lain juga berkesempatan untuk ditumbuh-kembangkan terutama dalam kaitannya dengan konstruksi berfikir. Meskipun demikian, implementasi pelaksanaan program ini memerlukan evaluasi, guna memutuskan apakah program ini layak dilanjutkan ataukah tidak, selain karena diperlukannya penemuan terhadap fokus peningkatan kualitas pembelajaran secara menyeluruh guna menghasilkan rekomendasi dalam menentukan keputusan. Penelitian ini dilakukan dengan menggunakan pendekatan mixed-method desain triangulasi, guna mengevaluasi sebab-sebab efektifitas, kendala ataupun kegagalan pelaksanaan program. Populasi dalam penelitian ini adalah mahasiswa semester III jurusan Pendidikan Kimia UIN Sultan Syarif Kasim Riau, yang didukung oleh dosen, asisten laboratorium dan laboran dan pemilihan sampel dilakukan menggunakan teknik random sampling. Evaluasi program dalam penelitian ini dilakukan menggunakan model CIPP (Context, Input, Process, Product). Hasil penelitian menunjukkan bahwa program ini berjalan cukup efektif jika dilihat dari rata-rata keseluruhan nilai, mulai dari context, input, proses dan produk yang berada pada skor baik dan sangat baik, di mana skor evaluasi context dan input, lebih baik dibanding proses dan produk. Penelitian ini memberikan rekomendasi untuk terus meningkatkan penggunaan pemodelan dan simulasi laboratorium kimia, baik sebagai latihan sebelum praktikum maupun menggantikan praktikum yang sesungguhnya. Kata Kunci: pemodelan; simulasi laboratorium; praktikum kimia  Permalink/DOI: http://dx.doi.org/10.15408/es.v8i2.4394  

Calculating Energy Release Rate as a Function of Crack Length Using a Multiple-Step Crack Closure Technique in Tire Finite Element Models

2018 ◽  
Vol 46 (3) ◽  
pp. 130-152
Author(s):  
Dennis S. Kelliher
Keyword(s):  
Finite Element ◽  
Energy Release Rate ◽  
Crack Length ◽  
Energy Release ◽  
Crack Closure ◽  
Release Rate ◽  
Fatigue Behavior ◽  
Three Dimensions ◽  
Quantitative Prediction ◽  
Closure Technique

ABSTRACT When performing predictive durability analyses on tires using finite element methods, it is generally recognized that energy release rate (ERR) is the best measure by which to characterize the fatigue behavior of rubber. By addressing actual cracks in a simulation geometry, ERR provides a more appropriate durability criterion than the strain energy density (SED) of geometries without cracks. If determined as a function of crack length and loading history, and augmented with material crack growth properties, ERR allows for a quantitative prediction of fatigue life. Complications arise, however, from extra steps required to implement the calculation of ERR within the analysis process. This article presents an overview and some details of a method to perform such analyses. The method involves a preprocessing step that automates the creation of a ribbon crack within an axisymmetric-geometry finite element model at a predetermined location. After inflating and expanding to three dimensions to fully load the tire against a surface, full ribbon sections of the crack are then incrementally closed through multiple solution steps, finally achieving complete closure. A postprocessing step is developed to determine ERR as a function of crack length from this enforced crack closure technique. This includes an innovative approach to calculating ERR as the crack length approaches zero.

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