New Tension-Compression Damage Model for Complex Analysis of Concrete Structures

Abstract

A new damage model, based on continuum damage mechanics and simulating the opening, closing and reopening of cracks in concrete using only one surface of discontinuity, is proposed in this article. The model complies with the thermodynamics principles of non-reversible, isothermal and adiabatic processes. INTRODUCTIONMicro-cracking and sliding between granular particles cause the highly non-linear behavior of concrete (Oller 1988), and it is difficult to represent this behavior through constitutive models. These phenomena can be characterized by the cohesion and the inner friction angle, the softening stress strain curve and the volumetric dilatation (Tao and Phillips 2005). They cause the decrease of the material's elastic modulus and strength. If the material is exposed to alternating tensilecompressive stress states, the opening, closing and reopening of cracks can occur. These phenomena must be adequately represented by constitutive models ensuring continuity of the response to complex loads. Traditionally, constitutive models for concrete use the fracture mechanics theory (CFM) and the continuum damage mechanics theory (CDM). Classical fracture mechanics gives a basis for simulating the opening and closing of cracks. Hillerborg et al. (1976) describe the mechanical behavior of concrete by developing a non-linear fracture model and using the finite element

A Stress Measurement Method for Steel Strands Based on LC Oscillation

“…e vibrating wire strain gauge (VWSG) [16,17] and crack reopening method [18,19] are two kinds of methods to measure the existing prestressed structures. VWSG is a nondestructive technique; however, crack reopening method to detect existing stress is a semidestructive method.…”

A three-dimensional plasticity-damage constitutive model for timber under cyclic loads

“…To this end, one of the most common and successful techniques for modelling isotropic damage consists in replacing the tensor M in Eq. 7 by a scalar expression [6,7,22,23], which takes the form:…”

“…where p i and¯ i are the eigenvectors and eigenvalues of the e↵ective stress tensor, respectively. In this way, it becomes possible to manage independent damage mechanisms for tension and compression [5] and also to model indirectly the opening and closing of cracks when the material is subjected to reversible loads [22]. In order to obtain the principal values of the e↵ective stress tensor (¯ i ) and their associated eigenvectors (p i ), a spectral decomposition is performed.…”

“…Nevertheless, the di↵erent evolution of the elastic boundaries in tension and compression is governed by the two damage variables. Likewise, the influence of the loading in one direction on the elasticity boundary in the other direction is defined by the concepts of structural damage, characteristic of tensile failure, and constitutive damage, characteristic of compressive failure [22]. The structural damage in tension does not a↵ect the sti↵ness degradation or the strength of the material when a reversed load is applied in compression (sti↵ness recovery).…”

Formulación, implementación y validación de un modelo de daño escalar para materiales frágiles aplicado a elementos sólidos tridimensionales

“…The experimental results published by Gopalaratnam et al (1985) are used in simple concrete specimens for validating the model under direct tensile stresses. Additionally, the results obtained in the numerical model with exponential softening, developed by Paredes et al (2016), are incorporated.…”