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contact_detector_inline_impl.hh
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			/**
			* Copyright (©) 2019-2023 EPFL (Ecole Polytechnique Fédérale de Lausanne)
			* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
			*
			* This file is part of Akantu
			*
			* Akantu is free software: you can redistribute it and/or modify it under the
			* terms of the GNU Lesser General Public License as published by the Free
			* Software Foundation, either version 3 of the License, or (at your option) any
			* later version.
			*
			* Akantu 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 Lesser General Public License for more
			* details.
			*
			* You should have received a copy of the GNU Lesser General Public License
			* along with Akantu. If not, see <http://www.gnu.org/licenses/>.
			*/

			/* -------------------------------------------------------------------------- */
			#include "contact_detector.hh"
			/* -------------------------------------------------------------------------- */

			#ifndef __AKANTU_CONTACT_DETECTOR_INLINE_IMPL_CC__
			#define __AKANTU_CONTACT_DETECTOR_INLINE_IMPL_CC__

			namespace akantu {

			/* -------------------------------------------------------------------------- */
			template <class Derived, std::enable_if_t<aka::is_vector_v<Derived>> *>
			inline bool ContactDetector::checkValidityOfProjection(
			Eigen::MatrixBase<Derived> & projection) const {
			Real tolerance = 1e-3;
			return std::all_of(projection.begin(), projection.end(),
			[&tolerance](auto && xi) {
			return (xi > -1.0 - tolerance) or (xi < 1.0 + tolerance);
			});
			}

			/* -------------------------------------------------------------------------- */
			template <class Derived>
			inline void ContactDetector::coordinatesOfElement(
			const Element & el, Eigen::MatrixBase<Derived> & coords) const {
			coords = mesh.extractNodalValuesFromElement(positions, el);
			}

			/* -------------------------------------------------------------------------- */
			template <class Derived, std::enable_if_t<aka::is_vector_v<Derived>> *>
			inline void ContactDetector::computeCellSpacing(
			Eigen::MatrixBase<Derived> & spacing) const {
			spacing.fill(std::sqrt(2.0) * max_dd);
			}

			/* -------------------------------------------------------------------------- */
			inline void
			ContactDetector::constructGrid(SpatialGrid<Idx> & grid, BBox & bbox,
			const Array<Idx> & nodes_list) const {
			auto position_it = make_view(this->positions, spatial_dimension).begin();
			auto to_grid = [&](auto node) {
			auto && pos = position_it[node];
			if (bbox.contains(pos)) {
			grid.insert(node, pos);
			}
			};

			std::for_each(nodes_list.begin(), nodes_list.end(), to_grid);
			}

			/* -------------------------------------------------------------------------- */
			inline void
			ContactDetector::constructBoundingBox(BBox & bbox,
			const Array<Idx> & nodes_list) const {
			auto to_bbox = [&](auto node) {
			auto && pos = make_view(this->positions, spatial_dimension).begin()[node];
			bbox += pos;
			};

			std::for_each(nodes_list.begin(), nodes_list.end(), to_bbox);

			Vector<Real> lower_bound = bbox.getLowerBounds().array() - max_bb;
			Vector<Real> upper_bound = bbox.getUpperBounds().array() + max_bb;

			bbox.setLowerBounds(lower_bound);
			bbox.setUpperBounds(upper_bound);

			AKANTU_DEBUG_INFO("BBox" << bbox);
			}

			/* -------------------------------------------------------------------------- */
			inline void ContactDetector::computeMaximalDetectionDistance() {
			Real elem_size;
			Real max_elem_size = std::numeric_limits<Real>::min();
			Real min_elem_size = std::numeric_limits<Real>::max();

			auto & master_nodes = this->surface_selector->getMasterList();

			for (auto & master : master_nodes) {
			Array<Element> elements;
			this->mesh.getAssociatedElements(master, elements);

			for (auto element : elements) {
			Int nb_nodes_per_element = mesh.getNbNodesPerElement(element.type);
			Matrix<Real> elem_coords(spatial_dimension, nb_nodes_per_element);
			this->coordinatesOfElement(element, elem_coords);

			elem_size = FEEngine::getElementInradius(elem_coords, element.type);
			max_elem_size = std::max(max_elem_size, elem_size);
			min_elem_size = std::min(min_elem_size, elem_size);
			}
			}

			AKANTU_DEBUG_INFO("The maximum element size : " << max_elem_size);

			this->min_dd = min_elem_size;
			this->max_dd = max_elem_size;
			this->max_bb = max_elem_size;
			}

			/* -------------------------------------------------------------------------- */
			inline Vector<Idx>
			ContactDetector::constructConnectivity(Idx & slave,
			const Element & master) const {
			auto && master_conn = this->mesh.getConnectivity(master);

			Vector<Idx> elem_conn(master_conn.size() + 1);
			elem_conn[0] = slave;
			elem_conn.block(1, 0, master_conn.size(), 1) = master_conn;

			return elem_conn;
			}

			/* -------------------------------------------------------------------------- */
			template <class Derived, std::enable_if_t<aka::is_vector_v<Derived>> *>
			inline void ContactDetector::computeNormalOnElement(
			const Element & element, Eigen::MatrixBase<Derived> & normal) const {
			Matrix<Real> vectors(spatial_dimension, spatial_dimension - 1);
			this->vectorsAlongElement(element, vectors);

			switch (this->spatial_dimension) {
			case 2: {
			normal = Math::normal(vectors);
			break;
			}
			case 3: {
			normal = Math::normal(vectors.col(0), vectors.col(1));
			break;
			}
			default: {
			AKANTU_ERROR("Unknown dimension : " << spatial_dimension);
			}
			}

			// to ensure that normal is always outwards from master surface
			const auto & element_to_subelement =
			mesh.getElementToSubelement(element.type)(element.element);

			Vector<Real> outside = mesh.getBarycenter(element);

			// check if mesh facets exists for cohesive elements contact
			Vector<Real> inside;
			if (mesh.isMeshFacets()) {
			inside = mesh.getMeshParent().getBarycenter(element_to_subelement[0]);
			} else {
			inside = mesh.getBarycenter(element_to_subelement[0]);
			}

			auto projection = (outside - inside).dot(normal);

			if (projection < 0) {
			normal *= -1.0;
			}
			}

			/* -------------------------------------------------------------------------- */
			template <class Derived>
			inline void ContactDetector::vectorsAlongElement(
			const Element & el, Eigen::MatrixBase<Derived> & vectors) const {
			auto nb_nodes_per_element = Mesh::getNbNodesPerElement(el.type);

			Matrix<Real> coords(spatial_dimension, nb_nodes_per_element);
			this->coordinatesOfElement(el, coords);

			for (auto i : arange(spatial_dimension - 1)) {
			vectors(i) = coords(i + 1) - coords(0);
			}
			}

			/* -------------------------------------------------------------------------- */
			template <class Derived1, class Derived2,
			std::enable_if_t<aka::are_vectors<Derived1, Derived2>::value> *>
			inline Real
			ContactDetector::computeGap(const Eigen::MatrixBase<Derived1> & slave,
			const Eigen::MatrixBase<Derived2> & master) const {
			auto gap = (master - slave).norm();
			return gap;
			}

			/* -------------------------------------------------------------------------- */
			inline void ContactDetector::filterBoundaryElements(
			const Array<Element> & elements, Array<Element> & boundary_elements) const {
			for (auto elem : elements) {
			const auto & element_to_subelement =
			mesh.getElementToSubelement(elem.type)(elem.element);

			// for regular boundary elements
			if (element_to_subelement.size() == 1 and
			element_to_subelement[0].kind() == _ek_regular) {
			boundary_elements.push_back(elem);
			continue;
			}

			// for cohesive boundary elements
			UInt nb_subelements_regular = 0;
			for (auto subelem : element_to_subelement) {
			if (subelem == ElementNull) {
			continue;
			}

			if (subelem.kind() == _ek_regular) {
			++nb_subelements_regular;
			}
			}

			auto nb_subelements = element_to_subelement.size();

			if (nb_subelements_regular < nb_subelements) {
			boundary_elements.push_back(elem);
			}
			}
			}

			/* -------------------------------------------------------------------------- */
			template <class Derived, std::enable_if_t<aka::is_vector_v<Derived>> *>
			inline bool ContactDetector::isValidSelfContact(
			const Idx & slave_node, const Real & gap,
			const Eigen::MatrixBase<Derived> & normal) const {
			Idx master_node{-1};

			// finding the master node corresponding to slave node
			auto it = std::find_if(
			contact_pairs.begin(), contact_pairs.end(),
			[slave_node](auto && pair) { return pair.first == slave_node; });
			master_node = it->second;

			auto && slave_elements = this->mesh.getAssociatedElements(slave_node);

			// Check 1 : master node is not connected to elements connected to
			// slave node
			Vector<Real> slave_normal(spatial_dimension);

			auto predicate = [](auto && element) {
			return element.kind() == _ek_regular;
			};

			for (auto && element : filter_if(slave_elements, predicate)) {
			auto && connectivity = this->mesh.getConnectivity(element);

			auto coords = mesh.extractNodalValuesFromElement(positions, element);

			// finding the normal at slave node by averaging of normals
			auto normal = GeometryUtils::normal(mesh, coords, element);
			slave_normal = slave_normal + normal;

			auto node_iter =
			std::find(connectivity.begin(), connectivity.end(), master_node);
			if (node_iter != connectivity.end()) {
			return false;
			}
			}

			// Check 2 : if gap is twice the size of smallest element
			if (std::abs(gap) > 2.0 * min_dd) {
			return false;
			}

			// Check 3 : check the directions of normal at slave node and at
			// master element, should be in opposite directions
			auto norm = slave_normal.norm();
			if (norm != 0) {
			slave_normal /= norm;
			}

			auto product = slave_normal.dot(normal);

			return not(product >= 0);
			}

			} // namespace akantu

			#endif /* __AKANTU_CONTACT_DETECTOR_INLINE_IMPL_CC__ */

rAKA/src/model/contact_mechanics/contact_detector_inline_impl.hhb9b88cb9b5f2features/friction_examp…

contact_detector_inline_impl.hhView Options

rAKA/src/model/contact_mechanics/contact_detector_inline_impl.hh
b9b88cb9b5f2features/friction_examp…

contact_detector_inline_impl.hh
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