xref: /libCEED/examples/solids/src/boundary.c (revision d4cc18453651bd0f94c1a2e078b2646a92dafdcc) !

// Copyright (c) 2017-2026, Lawrence Livermore National Security, LLC and other CEED contributors.
// All Rights Reserved. See the top-level LICENSE and NOTICE files for details.
//
// SPDX-License-Identifier: BSD-2-Clause
//
// This file is part of CEED:  http://github.com/ceed

/// @file
/// Boundary condition functions for solid mechanics example using PETSc

#include "../include/boundary.h"

#include <ceed.h>
#include <petscsys.h>

// -----------------------------------------------------------------------------
// Boundary Functions
// -----------------------------------------------------------------------------
// Note: If additional boundary conditions are added, an update is needed in elasticity.h for the boundaryOptions variable.

// BCMMS - boundary function
// Values on all points of the mesh is set based on given solution below for u[0], u[1], u[2]
PetscErrorCode BCMMS(PetscInt dim, PetscReal load_increment, const PetscReal coords[], PetscInt num_comp_u, PetscScalar *u, void *ctx) {
  PetscScalar x = coords[0];
  PetscScalar y = coords[1];
  PetscScalar z = coords[2];

  PetscFunctionBeginUser;

  u[0] = exp(2 * x) * sin(3 * y) * cos(4 * z) / 1e8 * load_increment;
  u[1] = exp(3 * y) * sin(4 * z) * cos(2 * x) / 1e8 * load_increment;
  u[2] = exp(4 * z) * sin(2 * x) * cos(3 * y) / 1e8 * load_increment;

  PetscFunctionReturn(PETSC_SUCCESS);
};

#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

// BCClamp - fix boundary values with affine transformation at fraction of load increment
PetscErrorCode BCClamp(PetscInt dim, PetscReal load_increment, const PetscReal coords[], PetscInt num_comp_u, PetscScalar *u, void *ctx) {
  PetscScalar x          = coords[0];
  PetscScalar y          = coords[1];
  PetscScalar z          = coords[2];
  PetscScalar(*clampMax) = (PetscScalar(*))ctx;

  PetscFunctionBeginUser;
  PetscScalar
      // Translation vector
      lx = clampMax[0] * load_increment,
      ly = clampMax[1] * load_increment, lz = clampMax[2] * load_increment,
      // Normalized rotation axis
      kx = clampMax[3], ky = clampMax[4], kz = clampMax[5],
      // Rotation polynomial
      c_0 = clampMax[6] * M_PI, c_1 = clampMax[7] * M_PI, cx = kx * x + ky * y + kz * z,
      // Rotation magnitude
      theta     = (c_0 + c_1 * cx) * load_increment;
  PetscScalar c = cos(theta), s = sin(theta);

  u[0] = lx + s * (-kz * y + ky * z) + (1 - c) * (-(ky * ky + kz * kz) * x + kx * ky * y + kx * kz * z);
  u[1] = ly + s * (kz * x + -kx * z) + (1 - c) * (kx * ky * x + -(kx * kx + kz * kz) * y + ky * kz * z);
  u[2] = lz + s * (-ky * x + kx * y) + (1 - c) * (kx * kz * x + ky * kz * y + -(kx * kx + ky * ky) * z);
  PetscFunctionReturn(PETSC_SUCCESS);
};