Stress resultants definition
 @STRESS_RESULTANTS_DEFINITION {
 @STRESS_RESULTANTS_NAME {StrResName} {
 @STRUCTURE_TYPE {StrType}
 @LOADING {
 @SCALING_FACTOR {sca}
 @FORCES {F_{1}, F_{2}, F_{3}}
 @MOMENTS {M_{1}, M_{2}, M_{3}}
 }
 @LOADING {
 @SCALING_FACTOR {sca}
 @FORCES {N_{1}, N_{2}, N_{12}}
 @MOMENTS {M_{1}, M_{2}, M_{12}}
 @SHEAR_FORCES {Q_{1}, Q_{2}}
 @DERIVATIVES {d_{1}, d_{2}}
 }
 @LOADING {
 }
 @APPLIED_AT_CENTERS {FlagCenter}
 @APPLICATION_POINT_LOCATION {x_{2a}, x_{3a}}
 @COMMENTS {CommentText}
 }
 }

...
Introduction
External loads are applied to beam, plates, and shells, and consequently, stress resultants develop at any point in the structure. Dymore is a finite element based tool for the comprehensive analysis of flexible multibody system. In particular, it features geometrically exact beam and plate/shell elements. These geometrically exact elements predict the dynamic response of the structure and evaluate time histories of stress resultants at any point along the beam's span or over the plate's midsurface. Given these stress resultants, SectionBuilder evaluates the threedimensional stress field at any point of the beam's crosssection. The Dymore/SectionBuilder interface explains this process in more details.
The threedimensional state of stress at any point of the beam's crosssection depends on the stress resultants at that point along the beam's span.
Flag StrType can take two values only.
 If StrType = BEAM, the stress resultants defined here correspond to those acting on the crosssection of a beam. This case is discussed in section stress resultants for beams.
 If StrType = PLATE, the stress resultants defined here correspond to those acting on the normal material line of a plate or shell.This case is discussed in section stress resultants for plates and shells.
Stress resultants for beams
Figure 1. Stress resultants acting on the beam's crosssection.
For beams, the stress resultants over a typical crosssection are defined by means of a force array and of a moment array.
 The components of the force vector acting on the beam's crosssection and resolved along axes b_{1}, b_{2}, and b_{3} are denoted F_{1}, F_{2}, and F_{3}, respectively, as shown in fig. 1. F_{1} is the axial force and F_{2} and F_{3} the transverse shear forces acting along unit vectors b_{2}, and b_{3}, respectively. These forces are applied at point O, the origin of the axis system.
 The components of the moment vector acting on the beam's crosssection and resolved about axes b_{1}, b_{2}, and b_{3} are denoted M_{1}, M_{2}, and M_{3}, respectively, as shown in fig. 1. M_{1} is the twisting moment or torque, and M_{2} and M_{3} the bending moments about unit vectors b_{2} and b_{3}, respectively.
 The force array is defined as F^{T} = {F_{1}, F_{2}, F_{3}}.
 The moment array is defined as M^{T} = {M_{1}, M_{2}, M_{3}}.
It is possible to change the point of application of the loading to another point of the crosssection, or to refer these forces and moments to the centroid and shear center of the section.
Notes
 For beams, a single @LOADING section should appear that contains the following input only: a scaling factor, sca, a force array, F, and a moment array, M.
 The scaling factor, sca, is a multiplicative factor that will affect both the force and the moment arrays. (Default value: sca = 1.0.)
 The force array, F, defines the forces acting on the crosssection. (Default value: F^{T} = {0.0, 0.0, 0.0}.)
 The moment array, M, defines the moments acting on the crosssection. (Default value: M^{T} = {0.0, 0.0, 0.0}.)
 If FlagCenter = YES, the axial force, F_{1}, is applied at the centroid and the transverse shear forces, F_{2} and F_{3}, are applied at the shear center, as depicted in fig. 2. (Default value: FlagCenter = NO)
 It is sometimes convenient to be able to apply the loads at an arbitrary point of the crosssection. If the application point is defined, the forces, F_{1}, F_{2}, F_{3}, will be applied at point A with coordinates x_{2a} and x_{3a}, as depicted in fig. 2.
Figure 2. Left figure: forces are applied at point A, with coordinates x_{2a} and x_{3a}.
Right figure: transverse shear forces are applied at the shear center, axial force at the centroid.
Stress resultants for plates and shells
Figure 1. Stress resultants acting acting on a differential element of the plate.
For plates or shells, the stress resultants over a differential element of the structure are defined defined by means of an inplane load array, a transverse shear force array, and a moment array.
 The components of the force vector acting on a face normal to unit vector b_{1} and resolved along unit vectors b_{1}, b_{2}, and b_{3} are denoted N_{1}, N_{12}, and Q_{1}, respectively, as shown in fig. 1. The components of the force vector acting on a face normal to unit vector b_{2} and resolved along unit vectors b_{1}, b_{2}, and b_{3} are denoted N_{12}, N_{2}, and Q_{2}, respectively, as shown in fig. 1. These forces are applied at point O, the origin of the axis system, typically located at the plate's midplane.
 The components of the moment vector acting on a face normal to unit vector b_{1} and resolved along unit vectors b_{1} and b_{2} are denoted M_{12} and M_{2}, respectively, as shown in fig. 1. The components of the moment vector acting on a face normal to unit vector b_{2} and resolved along unit vectors b_{1} and b_{2} are denoted M_{1} and  M_{12}, respectively, as shown in fig. 1.
 The inplane force array is defined as N^{T} = {N_{1}, N_{2}, N_{12}}.
 The transverse shear force array is defined as Q^{T} = {Q_{1}, Q_{2}}.
 The moment array is defined as M^{T} = {M_{1}, M_{2}, M_{12}}.
Notes
 For plates and shells, multiple @LOADING sections can appear that contains the following input only: a scaling factor, sca, an inplane force array, F, a transverse shear force array, Q, a moment array, M, and a definition of the derivative level.
 The scaling factor, sca, is a multiplicative factor that will affect the inplane force, transverse shear force, and moment arrays. (Default value: sca = 1.0.)
 The inplane force array, N, defines the inplane forces acting on the normal material line. (Default value: N^{T} = {0.0, 0.0, 0.0}.)
 The transverse shear force array, Q, defines the transverse shear forces acting on the normal material line. (Default value: Q^{T} = {0.0, 0.0}.)
 The moment array, M, defines the moments acting on the normal material line. (Default value: M^{T} = {0.0, 0.0, 0.0}.)
 The loading arrays defined in each section define the loading or its spatial derivatives. If d_{1} = 0 and d_{2} = 0, the inplane force array provides the loading at that point of the plate, N. If d_{1} = i and d_{2} = j, the inplane force array provides the spatial derivative of the loading at that point, dN/(dx_{1}^{i} dx_{2}^{j}). (Default value: d_{1} = 0 and d_{2} = 0.)