Creep and Creep Recovery Response of Load Cells Tested According to U.S. and International Evaluation Procedures
نویسندگان
چکیده
The 60 min creep data from National Type Evaluation Procedure (NTEP) tests performed at the National Institute of Standards and Technology (NIST) on 65 load cells have been analyzed in order to compare their creep and creep recovery responses, and to compare the 60 min creep with creep over shorter time periods. To facilitate this comparison the data were fitted to a multiple-term exponential equation, which adequately describes the creep and creep recovery responses of load cells. The use of such a curve fit reduces the effect of the random error in the indicator readings on the calculated values of the load cell creep. Examination of the fitted curves show that the creep recovery responses, after inversion by a change in sign, are generally similar in shape to the creep response, but smaller in magnitude. The average ratio of the absolute value of the maximum creep recovery to the maximum creep is 0.86; however, no reliable correlation between creep and creep recovery can be drawn from the data. The fitted curves were also used to compare the 60 min creep of the NTEP analysis with the 30 min creep and other parameters calculated according to the Organization Internationale de Métrologie Légale (OIML) R 60 analysis. The average ratio of the 30 min creep value to the 60 min value is 0.84. The OIML class C creep tolerance is less than 0.5 of the NTEP tolerance for classes III and III L.
منابع مشابه
Creep Behavior of Biodegradable Triple-Component Nanocomposites Based on PLA/PCL/Bioactive Glass for ACL Interference Screws
Background: The short-time creep behavior for a series of biodegradable nanocomposites which is used as implantable device into body is a crucial factor. In the current paper, we aimed to study the effect of bioactive glass nanoparticles (BGn) on creep and creep-recovery behaviors of PLA/PCL blends at different given load and different applied temperatures. Method: A series of biodegradab...
متن کاملCyclic Behavior of Beams Based on the Chaboche Unified Viscoplastic Model
In this paper, ratcheting behavior of beams subjected to mechanical cyclic loads at elevated temperature, using the rate dependent Chaboche unified viscoplastic model with combined kinematic and isotropic hardening theory of plasticity, is investigated. A precise and general numerical scheme, using the incremental method of solution, is developed to obtain the cyclic inelastic creep and plastic...
متن کاملInvestigation of Geotextile Yarn Effects on Improvement of Long-Term Deformation of Sandy Soil
Accurate predictions of the amount and the rate of long- term deformation of reinforced soils under an applied load are important key issue in geotechnical engineering, in which the deformation of soil develops with time at a state of constant effective stress. Since geosynthetic is generally considered creep sensitive therefore, evaluation of creep behavior of geosynthetic reinforced soil (GRS...
متن کاملMechanical Properties and Spring -Back Investigation in Creep Age Forming Process of 7075 Al Alloy
Creep age forming (CAF) process is a novel metal forming method with major benefits including improved mechanical properties and cost reduction for aviation industry applications. CAF happens due to creep phenomenon and stress-release during the artificial aging of heat-treatable aluminum alloys. In this work, the creep age forming of 7075 Aluminum alloy at 120, 150 and 180 °C for 6, 24 and 48...
متن کاملDevelopment of a new creep testing equipment to obtain long-term deformation parameters of salt rocks
Creep phenomenon in rock engineering plays a key role in development of underground spaces as they must be stable enough for a long period of time. Current research involved designing and manufacturing of a new creep testing machine. The equipment is capable to perform simultaneous light-duty creep tests on more than one cylindrical rock samples at a very low cost.To evaluate the equipment’s pe...
متن کامل