From 0041844e39b7d33630cb4ee98ab0001e7b844d00 Mon Sep 17 00:00:00 2001
From: Jukka Aho <ahojukka5@gmail.com>
Date: Sat, 9 May 2026 16:49:06 +0300
Subject: [PATCH] refactor(domains): remove shells/api.jl stub

Remove placeholder shell domain exports until a shell kernel lands.
---
 src/domains/shells/api.jl | 100 --------------------------------------
 1 file changed, 100 deletions(-)
 delete mode 100644 src/domains/shells/api.jl

diff --git a/src/domains/shells/api.jl b/src/domains/shells/api.jl
deleted file mode 100644
index c358821..0000000
--- a/src/domains/shells/api.jl
+++ /dev/null
@@ -1,100 +0,0 @@
-# This file is a part of JuliaFEM.
-# License is MIT: see https://github.com/JuliaFEM/JuliaFEM.jl/blob/master/LICENSE.md
-
-"""
-Shell formulation API definitions.
-
-This file defines shell-specific abstract types and formulation theories.
-Must be included after core api.jl.
-"""
-
-# ============================================================================
-# SHELL FORMULATION THEORIES
-# ============================================================================
-
-"""
-    AbstractShellTheory
-
-Abstract type for shell theory variants.
-
-Shell theories differ in how they model transverse shear deformation and thickness effects.
-
-# Concrete Theories
-- `ReissnerMindlin`: Thick shells (includes transverse shear)
-- `KirchhoffLove`: Thin shells (no transverse shear)
-
-# See Also
-- [`ShellFormulation`](@ref)
-"""
-abstract type AbstractShellTheory end
-
-"""
-    ReissnerMindlin <: AbstractShellTheory
-
-Reissner-Mindlin shell theory (thick shells, includes shear).
-
-Assumptions:
-- Normals to mid-surface remain straight but NOT perpendicular
-- Transverse shear deformation included
-- Valid for thick shells (h/L > 1/20)
-- 5 DOFs per node: 3 displacements + 2 rotations
-
-# Usage
-```julia
-formulation = ShellFormulation{ReissnerMindlin}()
-physics = Physics(
-    formulation=formulation,
-    field=DisplacementRotation{3}(),
-    mesh=shell_mesh,
-    material=steel
-)
-```
-"""
-struct ReissnerMindlin <: AbstractShellTheory end
-
-"""
-    KirchhoffLove <: AbstractShellTheory
-
-Kirchhoff-Love shell theory (thin shells, no shear).
-
-Assumptions:
-- Normals to mid-surface remain straight and perpendicular
-- No transverse shear deformation
-- Valid for thin shells (h/L < 1/20)
-- 3 DOFs per node: 3 displacements (rotations computed from displacements)
-
-# Usage
-```julia
-formulation = ShellFormulation{KirchhoffLove}()
-physics = Physics(
-    formulation=formulation,
-    field=Displacement{3}(),  # Only displacements, rotations implicit
-    mesh=shell_mesh,
-    material=aluminum
-)
-```
-"""
-struct KirchhoffLove <: AbstractShellTheory end
-
-"""
-    ShellFormulation{Theory<:AbstractShellTheory} <: AbstractFormulation
-
-Shell element formulation with theory variant.
-
-# Type Parameter
-- `Theory`: Shell theory type (ReissnerMindlin or KirchhoffLove)
-
-# Examples
-```julia
-# Thick shell (includes shear)
-ShellFormulation{ReissnerMindlin}()
-
-# Thin shell (classical theory)
-ShellFormulation{KirchhoffLove}()
-```
-
-# Fields per Node
-- Reissner-Mindlin: 5 DOFs (ux, uy, uz, θx, θy)
-- Kirchhoff-Love: 3 DOFs (ux, uy, uz) - rotations implicit
-"""
-struct ShellFormulation{Theory<:AbstractShellTheory} <: AbstractFormulation end