YLD0418P.h

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/*******************************************************************************
 * Copyright (C) 2017-2025 Theodore Chang
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ******************************************************************************/
#ifndef YLD0418P_H
#define YLD0418P_H
 
#include <Material/Material3D/Material3D.h>
#include <Toolbox/Expression.h>
#include <Toolbox/ResourceHolder.h>
 
struct DataYLD0418P {
    struct Saturation {
        Saturation(const double R, const double B)
            : rate(R)
            , bound(B) {}
 
        const double rate, bound;
 
        const bool active = rate > 0. && bound > 0.;
    };
 
    const vec modulus, ratio, parameter;
    const double exponent;
    const double ref_stress; // reference stress for scaling
 
    const Saturation kin;
};
 
class YLD0418P final : protected DataYLD0418P, public Material3D {
    static constexpr double two_third = 2. / 3.;
    static const double root_two_third;
    static constexpr unsigned max_iteration = 20u;
    static constexpr uword sa{0};
    static const span sb, sc;
    static const mat unit_dev_tensor;
 
    const unsigned hardening_tag;
 
    ResourceHolder<Expression> hardening_expression;
 
    mat66 dev_ini_stiffness;
    mat66 C1, C2;
 
    [[nodiscard]] std::pair<double, double> compute_hardening(const double pe) const {
        if(const auto k = hardening_expression->evaluate(pe).at(0); k >= 0.) return {k, hardening_expression->gradient(pe).at(0)};
 
        return {0., 0.};
    };
 
    using yield_t = std::tuple<const double, const vec6, mat66>;
 
    [[nodiscard]] yield_t compute_yield_surface(const vec3&, const mat33&, const vec3&, const mat33&) const;
 
    int with_kinematic();
    int without_kinematic();
 
public:
    YLD0418P(
        unsigned, // tag
        vec&&,    // elastic modulus
        vec&&,    // poissons ratio
        vec&&,    // parameter (18)
        double,   // exponent
        double,   // reference stress
        unsigned, // hardening expression tag
        double,   // kinematic rate
        double,   // kinematic bound
        double    // density
    );
 
    int initialize(const shared_ptr<DomainBase>&) override;
 
    unique_ptr<Material> get_copy() override;
 
    int update_trial_status(const vec&) override;
 
    int clear_status() override;
    int commit_status() override;
    int reset_status() override;
 
    void print() override;
};
 
#endif