Numerical stress analysis of resin cracking in LSI plastic packages under temperature cyclic loading — Part III: Material properties and package geometries

1998 ◽  
Vol 21 (4) ◽  
pp. 407-412 ◽  
Author(s):  
Takehiro Saitoh ◽  
Hidehito Matsuyama ◽  
Masayuki Toya
Keyword(s):  
Cyclic Loading ◽  
Stress Analysis ◽  
Material Properties ◽  
Plastic Packages

scholarly journals Material properties of Velcro fastenings

1982 ◽  
Vol 6 (2) ◽  
pp. 93-96
Author(s):  
D. L. Bader ◽  
M. J. Pearcy
Keyword(s):  
Cyclic Loading ◽  
Material Properties ◽  
Testing Machine ◽  
Force Extension ◽  
Instron Testing Machine ◽  
Attachment Strength

An assessment of the material properties of three types of touch and close fasteners (Velcro) in general orthopaedic usage is presented. The materials were tested under various loading regimes using an Instron testing machine. The force-extension curves were analyzed and values determined for both the stiffness and strength of the various attachments. Particular reference was made to the alteration in attachment strength after cyclic loading. The strength of the standard Velcro was found to be least affected after cyclic loading to simulate continuous usage. A recommendation is made on the specific application of each type of Velcro based on their material properties.

Elasto-plastic contact stress analysis of joints subjected to cyclic loading

1996 ◽  
Vol 60 (6) ◽  
pp. 1067-1077 ◽  
Author(s):  
K.Satish Kumar ◽  
B. Dattaguru ◽  
T.S. Ramamurthy ◽  
K.N. Raju
Keyword(s):  
Cyclic Loading ◽  
Stress Analysis ◽  
Contact Stress

Effect of Temperature on the Material Properties and the Results of Thermal Stress Analysis

2017 ◽  
Vol 729 ◽  
pp. 8-12
Author(s):  
Tae Kyung Kim ◽  
Dong Kwon Oh ◽  
Kwang Ju Lee
Keyword(s):  
Thermal Stress ◽  
Elastic Modulus ◽  
Stress Analysis ◽  
Material Properties ◽  
Room Temperature ◽  
Test System ◽  
Effect Of Temperature ◽  
Air Conditioning System ◽  
Thermal Stress Analysis ◽  
Different Levels

Use of correct values of material properties is important in structural analysis. When incorrect values are used in the analysis, engineers may end up with misleading conclusions. The magnitudes of elastic modulus and strength are usually measured from experiments at room temperature. When these values are used in the thermal stress analysis of structures, the results may not be reliable because the magnitudes of elastic modulus and strength depend on temperature. The temperature distribution of HVAC (Heating, Ventilation and Air Conditioning) system was analyzed. The material properties were measured using MTS810 material test system and MTS 651 environmental chamber at different levels of temperature. They were used in the thermal stress analysis of HVAC system. It was found that the results of thermal stress analysis were significantly different from the results using material properties which were measured from experiments at room temperature.

The Behavior of Salem Limestone in Cyclic Loading

1974 ◽  
Vol 14 (01) ◽  
pp. 19-24 ◽  
Author(s):  
S.S. Peng ◽  
E.R. Podnieks ◽  
P.J. Cain
Keyword(s):  
Fatigue Life ◽  
Cyclic Loading ◽  
Material Properties ◽  
High Frequency ◽  
Low Frequency ◽  
Tensile Loading ◽  
Cyclic Stress ◽  
Time Dependent ◽  
Mean Stress ◽  
Frequency Range

Abstract Specimens of Salem limestone were loaded cyclically at a frequency of 2 cycles/sec in uniaxial cyclic compression, tension, and compression-tension. The number of cycles to failure, maximum deformation for each cycle, and load-deformation hysteresis loops were recorded. The fatigue life and fatigue limit values under cyclic compressive loading are comparable with those under cyclic tensile loading, whereas under cyclic compressive-tensile loading they are considerably lower. Introduction The study of rock behavior in cyclic loading has been relatively ignored in the past, even though certain problems in rock mechanics are closely related to cyclic loading. These problems include the effects of percussive drilling and the vibrations generated by blasting. An understanding of the mechanisms of fatigue failure in rock can be expected to help improve drilling efficiency and prevent vibration damage caused by blasting. Because of the lack of bask information on rock behavior under cyclic loading, the Federal Bureau of Mines, Twin Cities Mining Research Center began in 1968 an extensive program for studying cyclic loading effects. This program included the investigation of the behavior of rock loaded cyclically at different frequencies under varying test geometries, loading configurations, and environments. In the high-frequency range, sonic power transducers are being used to apply cyclic loading at a frequency of 10,000 Hz, and an electromagnetic shaker is being used at frequencies from 100 to 1,000 Hz. In the low-frequency range, cyclic loading of 2 to 10 Hz is applied by a closed-loop servocontrolled electrohydraulic testing machine. In each frequency range, experiments are conducted to provide the following information: fatigue limits, fatigue life, energy dissipation, temperature induced in the specimen, and the time history of load and deformation. This paper presents the first phase of be results obtained on specimens of Salem limestone loaded in the low-frequency range. The early findings on the high-frequency effects were reported separately. Recently, the effect of cyclic loading on rock behavior has been receiving more attention and considerable information is being generated. General Loading Concept in Cyclic Loading In conventional strength tests the monotonic loading program is specified by the loading rate and control mode. For cyclic loading, where the load is a periodic function of time, the problem is more complex. To evaluate such material properties as fatigue life, the load must be described systematically and concisely in terms of physically significant parameters. parameters. For a general case, one approach is to divide the cyclic stress into time-independent and time-dependent components. The time-independent component (or mean stress) is the time average of the stress. A cyclic stress with an amplitude A and zero mean can be superimposed on this loading. For the usual case of cyclic loading with steady loading conditions, the stress can be described as follows.(1)= + (t), where f(t) is a periodic function of time, t, and can be represented by a sine or sawtooth wave. Other ways of describing the stress are available such as using the maximum and minimum stresses, which are related to the mean and amplitude:(2)max = . and(3)min = . The key issue is to describe the loading in terms that will correlate with the material properties of interest. The use of amplitude and mean stress to describe cyclic loading separates the time-dependent bona the time-independent portion of the stress because the effect of each portion of the loading should be investigated separately. In analyzing the effect of cyclic loading on rock, another significant factor is the large difference between the tensile strength and the compressive strength. P. 19

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