Experimental Research on Vibration Characteristics of Laminated Composite Cantilever Beam

2021 ◽  
Author(s):  
Rui Yang ◽  
Xiaobin Li ◽  
Hongxi Li
Keyword(s):  
Cantilever Beam ◽  
Optical Measurement ◽  
Laminated Composite ◽  
Experimental Methods ◽  
Test Methods ◽  
Vibration Characteristics ◽  
Test Method ◽  
Vibration Measurement ◽  
Vibration Test ◽  
Test Results

Abstract In this paper, the vibration characteristics of laminated composite cantilever beam is taken as the research object. Firstly, a vibration formula specific for laminated composite cantilever beam is derived, from which the low order natural frequency of laminated composite cantilever beam is calculated; Secondly, two experimental methods, electrical and optical measurement, are used to study the vibration characteristics of laminated composite cantilever beam, and the influence of different test methods, sensor types, number of measuring points and excitation methods on the test results are analyzed. Through the combination of theory and experiment, a test method that can be applied to the vibration test of composite material laminated structure cantilever beam is obtained. Based on the laser vibration measurement method in the optical method, the results show that the deviation between the experimental data and the theoretical solution is the smallest when the distance between the probe and the specimen is 0.5m and the sampling time is 5s by using the optical fiber vibrometer. The research content of this article can provide a reasonable reference for related vibration test research.

Test Method of the εrms-N Curves of Laminated Composite Beams

2008 ◽  
Vol 44-46 ◽  
pp. 311-316
Author(s):  
Chuang Shao ◽  
Sen Ge ◽  
Hua Tao ◽  
Claude Bathias
Keyword(s):  
Resonance Frequency ◽  
Fatigue Test ◽  
Laminated Composite ◽  
Test Method ◽  
Cantilever Beams ◽  
Test Results ◽  
Vibration Fatigue ◽  
The Difference ◽  
Double Cantilever Beams ◽  
Laminated Composite Beams

Two kinds of beam specimens made of composite laminated panel were designed and used to do vibration fatigue test for ε-N curves. the shapes of various simulated joint configurations for the specimens were adopted in order to get the accurate results. They were two kinds of double-cantilever beams supplied by T-mode stiffener and L-mode stiffener. All beam specimens were tested under the same shape of narrowband spectrum and the several loadings of random vibration by shaker excitation. The bandwidth of the narrowband random spectrum was 1/3 octave bandwidth whose centre frequency was the first resonance frequency of the cantilever beam, so that it reduced influences of the difference of specimens resonance frequency. Fitting vibration fatigue test results, the ε-N curves would be obtained then. The vibration test shows that this method of getting ε-N vibration curve is feasible. It can be used in practice.

Review of material test standardization status for the material qualification of laminated thermosetting composite structures

2020 ◽  
pp. 073168442095810
Author(s):  
Sang Yoon Park ◽  
Won Jong Choi
Keyword(s):  
Composite Materials ◽  
Material Properties ◽  
Composite Structures ◽  
Failure Modes ◽  
Laminated Composite ◽  
Test Methods ◽  
Test Method ◽  
Experimental Comparison ◽  
Laminated Composite Materials ◽  
Design Values

This paper presents a review of recent literature related to the static mechanical testing of thermoset-based carbon fiber reinforced composites and introduces a material qualification methodology to generate statistically-based allowable design values for aerospace application. Although most test methods have been found to be effective in determining the specific material properties by incorporating them into the material qualification and quality control provisions, a full validation to clarify the behavior of thermoset-based laminated composite materials is currently lacking, particularly with regard to the characterization of compressive, in-plane, interlaminar shear, and damage tolerance properties. The present study obtains information on the different types of test method that can be employed within the same material properties, and makes an in-depth experimental comparison based on the past literatures. A discussion on the scope of theoretical analysis involves a description of how the proposed test method can be adequate for obtaining more accurate material properties. This discussion is directly applicable to the assessment of material nonlinearity and the geometrical effect of specimens. Finally, the resulting failure modes and the effect of each material property are studied to aid the understanding of the load distribution and behavior of laminated composite materials.

Methods to Evaluate Cleaners and Sanitizers

1982 ◽  
Vol 45 (13) ◽  
pp. 1257-1260 ◽  
Author(s):  
DALE L. SCHEUSNER
Keyword(s):  
Test Methods ◽  
Test Method ◽  
Test Results ◽  
Standard Laboratory ◽  
Test Procedures ◽  
Laboratory Methods ◽  
Product Use ◽  
Cellulose Sponge ◽  
Equivalent Test ◽  
Recovery Methods

Methods to evaluate germicides can be grouped into three categories: standard laboratory tests, in-use tests and simulated-use tests. Standard laboratory methods, such as the Available Chlorine Germicidal Equivalent test, are specifically defined for reproducibility in any laboratory by any operator, but the test results often lack relevance to actual product-use conditions. In-use test methods are relevant to product-use; however, in-use test procedures do not permit proper controls to be included in the organism recovery methods. Contact plates give an estimate of organism numbers which is only 25% of the theoretical number of organisms present. Organism recovery using a swab, cellulose sponge or tube sampler give estimates of organisms ranging from 91 to 111% of theoretical. The tube sampler is a 1-in. length of flexible tubing having a 1-in. interior diameter and a smooth end, which can make a water-tight seal on a flat surface. Simulated use testing yields data which are relevant to actual product-use. A cafeteria tray is soiled, inoculated and cleaned in a manner to simulate actual product-use. This test method permits the necessary controls to be used. Tray-test reproducibility is as good as that of the other recovery methods tested and organism recovery is quantitative. The tray test provides a means for determining biological cleaning where the effect of both cleaning and germicidal activity are measured together.

Study on Vibration Properties of Fresh Concrete with Simple Test Method

2015 ◽  
Vol 1110 ◽  
pp. 267-270
Author(s):  
Yuji Yamada ◽  
Shinichiro Hashimoto ◽  
Chikanori Hashimoto ◽  
Takeshi Watanabe ◽  
Shigeyuki Date
Keyword(s):  
Fly Ash ◽  
Fresh Concrete ◽  
Experimental Methods ◽  
Vibration Characteristics ◽  
Test Method ◽  
Simple Test ◽  
Slump Test ◽  
Vibration Properties ◽  
Alternative Test ◽  
Alternative Test Method

It has been reported that, depending on the material used, batches of concrete having the same slump value behave differently when vibrated. It is therefore to be expected that batches of concrete having the same slump value and containing the same amount of powder will have different properties depending on the material used. However, these batches of concrete are treated as concrete of the same quality since, at present, no alternative test method has yet been established as a substitute for the slump test. This study proposed new simplified experimental methods for vibration properties of fresh concrete. By using these methods, the vibration characteristics of fresh concrete containing fly ash (FA) and containing a large amount of cement were exhibited.

scholarly journals Performance characteristics of polymerase chain reaction and histological methods for the detection of Haplosporidium nelsoni in the eastern oyster (Crassostrea virginica)

2015 ◽  
Vol 27 (4) ◽  
pp. 476-488 ◽  
Author(s):  
Nellie Gagné ◽  
Anne Veniot ◽  
Mary Stephenson ◽  
Carol McClure
Keyword(s):  
Polymerase Chain Reaction ◽  
Test Methods ◽  
Test Method ◽  
Performance Characteristics ◽  
Analytical Sensitivity ◽  
Test Results ◽  
Fitness For Purpose ◽  
Chain Reaction ◽  
Repeatability And Reproducibility ◽  
Polymerase Chain

Fitness for purpose and validation are increasingly becoming a benchmark in the development of test methods for the diagnosis of infectious diseases in aquatic animals. The design of the evaluation and the analysis of data are critical to demonstrate test method performance characteristics and fitness for purpose, as stated in the World Organization for Animal Health pathway for test validation. Three test methods for the detection of the oyster parasite Haplosporidium nelsoni were selected for the validation study described herein: histology, end-point polymerase chain reaction (PCR), and real-time PCR (qPCR). Preliminary work evaluated the analytical sensitivity and specificity of the PCR and qPCR assay in development. The following stage used test results on 100 oysters in 3 different laboratories to assess diagnostic sensitivity (DSe), diagnostic specificity (DSp), repeatability, and reproducibility. Repeatability and reproducibility were within 68–95%. The final part of the project evaluated DSe and DSp using test results on 400 oysters and results from the first 100 oysters tested. In the absence of a 100% gold standard test, latent class modeling methods were explored to characterize the tests (i.e., Bayesian analyses). For both PCR methods, DSe was >90%, and in the 60% range for histology, whereas DSp was >90% for all methods. Based on the results of this validation, a threshold cycle value of 30 for qPCR corresponds to the limit of sensitivity for histology where unreliable detection becomes more frequent, thus providing a threshold helpful in diagnostic settings where both histology and qPCR are used.

The Research of Negative Ion Test Method for Fabric

2013 ◽  
Vol 756-759 ◽  
pp. 138-140 ◽  
Author(s):  
Yun Sen Sun ◽  
Bo Qiu ◽  
Qing Shan Li
Keyword(s):  
Influence Factors ◽  
Test Methods ◽  
Test Method ◽  
Ion Concentration ◽  
Negative Ion ◽  
Testing Device ◽  
Test Results ◽  
Influence Of Temperature ◽  
Functional Textiles ◽  
Temperature And Humidity

We developed a device for automatic closed friction and analyzed its test results in this paper, which showed the influence factors in the test methods of textile negative ion occurrence amounts. The textile negative ion occurrence amounts in different time stages were tested in this process; the analysis of its influence of temperature and humidity has certain reference significance for improving testing device for testing textile negative ion concentration, on the basis, functional textiles were also studied. Finally, we put forward the influence factors in the test methods of textile negative ion occurrence amounts.

Transient Methods of Thermal Properties Measurement on Fibrous Materials

2009 ◽  
Vol 132 (3) ◽  
Author(s):  
Zuo Lei ◽  
Sukang Zhu ◽  
Ning Pan
Keyword(s):  
Fibrous Material ◽  
Local Heat ◽  
Test Methods ◽  
Test Method ◽  
Dual Phase ◽  
Fibrous Materials ◽  
Test Results ◽  
Main Factors ◽  
Transient Methods ◽  
Transfer Properties

Fibrous material is a complex porous medium and steady test methods are the main test approaches we currently depend on to study the heat transfer properties. The application of unsteady test methods on fibrous material is still not mature. In this paper, some systematic studies are taken to investigate this problem. By analyzing the main factors impacting the test results, it is found that the local heat convection potentially excited by imposing test temperature can be avoided by limiting the internal temperature gradient and the so-called dual-phase lagging effects are negligible so that the feasibility of the unsteady test method is verified via both theoretical analysis and experimental data.

scholarly journals THE ESTIMATION PROBLEMS OF THE FIRE HAZARD FOR VERTICALLY ORIENTED BUILDING PRODUCTS/VERTIKALIAI ORIENTUOTŲ STATYBINIŲ GAMINIŲ GAISRINIO PAVOJINGUMO ĮVERTINIMO PROBLEMOS

1999 ◽  
Vol 5 (1) ◽  
pp. 74-78 ◽  
Author(s):  
Albertas Nyderis
Keyword(s):  
Heat Transfer ◽  
Fire Protection ◽  
Fire Test ◽  
Test Methods ◽  
Test Method ◽  
Building Construction ◽  
Research Centre ◽  
Test Results ◽  
Solid Materials ◽  
Building Products

The Directive of new approach 89/106/EEC, which was prepared by Directorate General of the European Commission (DG III), defines the guidelines for development of fire protection in building construction. Six main directions for development of fire protection are defined in this Directive as well. Solid materials are most numerous among building products. Therefore a brief analysis of combustion process of these materials is presented in this article. F.Williams developed the theoretical principles of combustion. Phase transitions in the zone of combustion are analyzed in the theory. Formulas 1–4 describe this process. The process of combustion of solid materials is heterogeneous; therefore the model of pyrolysis is presented by 5 formulas. An intricate energy exchange takes place in real fires. The heat is being transferred in different ways. The most acceptable description of heat transfer is by means of radiation. Description of this process is presented in formulas 6–7. The heat transfer by means of radiation can be modelled and used for environment testing. The combustibility of building products can be examined by means of reaction of fire tests. In recent years tests for different building products were carried out according to ISO 5657 test methodology in the Fire Research Centre. Test results indicate that the time to sustained surface ignition for building products is inversely proportional to heat flux. This logarithmic dependence is presented in 8 formulas. Establishment of parameters of this logarithmic flow for different building products can prove this. This work was carried out during the process of verification of this hypothesis. Analysis of fire testing practice of vertically oriented building products in different countries shows that harmonized fire test methods for these products do not exist. Most of these test methods are based on presumption that the flame spread is possible only inside the building not considering the behaviour of facade in fire. The main idea of fire test method for element of vertically oriented building construction together with the principal scheme of test equipment are presented in the article as well. Further development of this idea leads to five questions, which should be answered to solve the problem. After the completion of this task and analysis of test results, all the information is to be submitted for further consideration.

scholarly journals Research on comprehensive load vibration test of electric vehicle motor controller unit

2021 ◽  
Vol 260 ◽  
pp. 03002
Author(s):  
Zhibiao Yan ◽  
Lingxiao Zhao ◽  
Huansheng Ma
Keyword(s):  
Electric Vehicle ◽  
Control Unit ◽  
Test Methods ◽  
Current Data ◽  
Test Method ◽  
Temperature Cycle ◽  
Vibration Test ◽  
Environmental Load ◽  
Electrical Load ◽  
Motor Controller

In this article, the vibration test standards and general test methods for electric vehicle motor control unit are introduced. New vibration test conditions are proposed based on the vibration data collected during the actual vehicle test. Using the vehicle output current data as the electrical load of the motor controller unit, and the temperature cycle as the environmental load, a comprehensive load vibration test method that integrates the electrical load and the environmental load is proposed. According to the test method, the equipment and test process of the comprehensive on-load vibration test of environmental load are determined. Summarized three important principles in the design of fixtures: lightweight, low damping, and no resonance. A novel testing method for motor controllers is proposed.

Dynamic Fracture Initiation: A Comparison of Two Experimental Methods

1979 ◽  
Vol 101 (2) ◽  
pp. 168-172 ◽  
Author(s):  
L. S. Costin ◽  
W. L. Server ◽  
J. Duffy
Keyword(s):  
Dynamic Fracture ◽  
Fracture Initiation ◽  
Experimental Methods ◽  
Test Methods ◽  
Test Results ◽  
Charpy Test ◽  
Dynamic Fracture Tests ◽  
Brown University ◽  
Fracture Tests ◽  
Good Agreement

This paper presents a comparison of dynamic fracture initiation results obtained from two independent experimental methods: (1) the instrumented version of the precracked Charpy test and (2) a new dynamic fracture test developed at Brown University (BU). Dynamic fracture tests were conducted using both methods on 4340 steel at room temperature and on 1018 cold-rolled steel (CRS) at temperatures over the range −157 to 107°C. This range covered temperatures on the lower shelf, the transition regime, and the upper shelf of the transition temperature curve. Stress intensity rates of K˙I = 2.2 × 105 MN-m−3/2/s and K˙I = 2.2 × 106 MN-m−3/2/s were used in the instrumented precracked Charpy and BU tests, respectively. In the analysis of test results, both elastic (KIc) and elastic-plastic (J-integral) fracture parameters were computed. Results of the two test methods were found to be generally in good agreement, except that some differences were observed between 1018 CRS test results on the upper shelf. Possible reasons for these differences are discussed.

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