فهرست مقالات Farzad Peyman


  • مقاله

    1 - Investigation of Failure Mechanism in Earth Dam upon Triggered Liquefaction
    Analytical and Numerical Methods in Mechanical Design , شماره 1 , سال 1 , بهار 2022
    The behavior of the earth-dam body as a soil structure made of cohesive soil in the core and non-cohesive soil as the core supports, including water interaction upstream through earthquake upon multi-line constitutive equations, is the aim of this paper. A multi-plane m چکیده کامل
    The behavior of the earth-dam body as a soil structure made of cohesive soil in the core and non-cohesive soil as the core supports, including water interaction upstream through earthquake upon multi-line constitutive equations, is the aim of this paper. A multi-plane mechanism-based approach is successfully employed for assigning post-liquefaction displacement of earth-dam structures. This approach is derived from total stress procedures with two major advantages:1) the triggering and post-liquefaction responses have been multi-lined into one analysis.2) the modeling of post-liquefaction element behavior is greatly improved.To sum up, a multi-plane-based framework is employed. The strength effects on integrated sampling planes and the resultant of this simulated multi-lined behavior are implemented for each finite element gauss point. This multi-plane-based model can also predict the effects of induced and inherent anisotropy plus the rotation of principal stress/strain axes through the plastic behavior of both cohesive and non-cohesive soils.The approach is presented through the simulation of the case history as the response of the lower San Fernando dam to the 1971 San Fernando earthquake. The magnitude and pattern of the predicted displacements are shown to be in good agreement with the measured values پرونده مقاله

  • مقاله

    2 - Investigation of The Mechanism of Change of Concrete Modulus Matrix in Monotonic Loading and its Numerical Analysis
    Analytical and Numerical Methods in Mechanical Design , شماره 1 , سال 1 , زمستان 2022
    The primary purpose of studying the behavior of concrete is to calculate its strength and deformation under environmental conditions and loading. In this regard, due to the structure and nature of concrete, non-isotropic in its experimental behavior at different loads i چکیده کامل
    The primary purpose of studying the behavior of concrete is to calculate its strength and deformation under environmental conditions and loading. In this regard, due to the structure and nature of concrete, non-isotropic in its experimental behavior at different loads is observed, considered in this research. Accordingly, by assuming a different linear elastic behavior in each loading increment and the experimental results, an attempt has been made to define a numerical linear-nonlinear behavior for concrete. Therefore, proportional numerical functions are defined based on the damage in the modulus of elasticity and the changes in the Poisson ratio of the concrete tested in monotonic loading types, the coefficients obtained from the related experimental results. The computational effects of these functions during the analytical method of the research cause the experimental behavior of concrete to be converted to numerical behavior. The validity of this numerical method is based on calibration and comparison with experimental results. In addition to hardening behavior, this numerical analysis can define softening behavior. پرونده مقاله

  • مقاله

    3 - Permeability Variation and Fracture/Crack Effects in Concrete/Rocks based on Multi-laminate Model
    Analytical and Numerical Methods in Mechanical Design , شماره 3 , سال 2 , تابستان 1402
    The permeability matrix of rock is a physical/mechanical characteristic that closely relates to the microstructure of this heterogeneous geomaterial, and the orientation of micro-cracks led to some naturally existing micro-cracks. Upon the effects of loading/unloading a چکیده کامل
    The permeability matrix of rock is a physical/mechanical characteristic that closely relates to the microstructure of this heterogeneous geomaterial, and the orientation of micro-cracks led to some naturally existing micro-cracks. Upon the effects of loading/unloading and high-temperature development, micro-cracks appear in critical zones of rock media that can effectively change the conductivity against gas or other fluids. Finally, macro cracks are generated and increase the porosity of the rock matrix on the distribution and geometrical arrangement. Consequently, the permeability becomes higher and depends on the stress/strain level of the rock body during loading/unloading and the passing fluidity interaction process. The influence of stress level and high temperature on rock's gas and water permeability has been studied in the literature. Fractured rock formations show vastly different properties, such as adsorption, etc., concerning permeability and storage capacity, thus giving rise to mass exchange processes between fractures and the surrounding matrix. This interaction between fracture and matrix impacts the flow and transport processes in the fractured subsurface, which can be observed on each scale considered for investigation purposes. The influence of fracture-matrix interaction has to be scrutinized upon the planned tests conforming to the natural condition when dealing with safety investigations or remediation possibilities. This paper shows some of the effects of fracture-matrix interaction and its geometry on groundwater flow in a saturated fractured rock/concrete media and the parameters describing those processes concerning different scales. A damage model concept contains fracture network generation, mesh generation, and appropriate discretization techniques based on presumed sampling between planes and polygons. The influence of a polygon matrix of finite porosity on the effective hydraulic conductivity tensor of a fractured system is illustrated by an example. In this research, we focus on determining the gas and water permeability of rock commonly used in transportation works, including loose/low strength and high strength/dense rock/concrete in interaction with pre-peak stress and damage level in post-peak behavior of rocks. پرونده مقاله