Calculation of Interaction Parameters from Immiscible Phase Diagram of Alkali Metal or Alkali Earth Metal-Halide System by Means of Subregular Solution Model

In this paper, the interaction parameters in the subregular solution model, λ1 and λ2, are regarded as a linear function of temperature, T. Therefore, the molar excess Gibbs energy of A-B binary system may be reexpressed as follows:Gm^E=xAxB[(λ11+λ12T)+(λ21+λ22T)xB]The calculation of the model parameters, λ11, λ12, λ21and λ22, was carried out numerically from the phase diagrams for 11 alkali metal-alkali halide or alkali earth metal-halide systems. In addition, artificial neural network trained by known data has been used to predict the values of these model parameters. The predicted results are in good agreement with the .calculated ones. The applicability of the subregular solution model to the alkali metal-alkali halide or alkali earth metal-halide systems were tested by comparing the available experimental composition along the boundary of miscibility gap with the calculated ones which were obtained by using genetic algorithm. The good agreement between the calculated and experimental results across the entire liquidus is valid evidence in support of the model.

COMPUTERIZED PREDICTION OF INTERACTION PARAMETERSAND PHASE DIAGRAMS OF CONTINUOUS SOLID SOLUTION OFBINARY ALLOY SYSTEMS

The artificial neural network method has been applied to the relationship between the atomic parameters and intemction packeters of binary alloy Phases, and the principle of thermodynamics in combination with artificial neural network method has been used for the computerized phase diagrams of continuous solid solution of bigamy alloy systems. The computerized phase diagrams well agree with the real phase diagmms.

Proper interpretation of sectional analysis results

Displacement control algorithms commonly used to evaluate axial force-bending moment(PM)diagrams may lead to incorrect interpretations of the strength envelopes for asymmetric sections.This paper aims to offer valuable insights by comparing existing displacement control algorithms with a newly proposed force control algorithm.The main focus is on the PM diagrams of three example sections that exhibit varying degrees of asymmetry.The comparative study indicates that conventional displacement control algorithms inevitably introduce non-zero out-of-plane bending moments.The reported PM diagram in such cases erroneously neglects the out-of-plane moment and fails to represent the strength envelope accurately.This oversight results in significant and unconservative errors when verifying the strength of asymmetric sections.

Structural strength deterioration of coastal bridge piers considering non-uniform corrosion in marine environments

In the aggressive marine environment over a long-term service period,coastal bridges inevitably sustain corrosion-induced damage due to high sea salt and humidity.This paper investigates the strength reduction of coastal bridges,especially focusing on the effects of non-uniform corrosion along the height of bridge piers.First,the corrosion initiation time and the degradation of reinforcement and concrete are analyzed for bridge piers in marine environments.To investigate the various damage modes of the concrete cover,a discretization method with fiber cells is used for calculating time-dependent interaction diagrams of cross-sections of the bridge piers at the atmospheric zone and the splash and tidal zone under a combination of axial force and bending moment.Second,the shear strength of these aging structures is analyzed.Numerical simulation indicates that the strength of a concrete pier experiences dramatic reduction from corrosion initiation to the spalling of the concrete cover.Strength loss in the splash and tidal zone is more significant than in the atmospheric zone when structures’service time is assumed to be the same.

Low Cycle Fatigue, Creep-Fatigue and Relaxation-Fatigue Tests on P91

Creep-fatigue is a damage mechanism where cyclic deformation damage （fatigue） is enhanced by creep damage and vice versa. Factors affecting the creep-fatigue damage are stress level （or, equivalently, strain range）, temperature, hold time period, material softening/hardening and number of cycles. Moreover, environmental effects can accelerate the creep-fatigue interaction （oxidation, hot corrosion, irradiation, etc.）. The activity described in this paper was planned to perform tests on 9Cr-lMo ferritic/martensitic steel （P91） combining fatigue cycles and constant tensile and compressive holding periods. A preliminary basic fatigue characterization campaign in the LCF （low cycle fatigue） regime was carried out by performing a series of strain controlled tests, each at the same temperature （550 ℃）, using two different values for the total strain range （1% and 0.6%） and the same total strain rate （2×10^-3 s^-1）. The tests were carried out with a strain ratio of-l, i.e., in fully reversed cyclic conditions. In this paper we illustrate the results obtained by testing in air P91 （9Cr-lMo） ferritic/martensitic steel, introducing different dwell periods （either in strain or load control） and obsetwing how these affect the fatigue life of the specimens. The final aim of the activity is to investigate how much detrimental is the effect of the holding periods on the fatigue life in order to validate the creep-fatigue interaction diagram presently adopted in RCC-MRx code for the P91 steel.