William Martins Vicente

Glued laminated timber (glulam) beams manufactured with glued steel bars can achieve improvements in their mechanical performance and the effects of the arrangement of steel bars in the cross-section are of technological interest. This study aimed to evaluate the mechanical behavior of beams with symmetric reinforcements (compression and tension zones) and beams with asymmetric reinforcements (compression zone), under loading imposed at the serviceability limit state. To achieve this goal, glulam beams with reinforcement ratios ranging from 0.5% to 4% were simulated using the finite element method. When compared to the nonreinforced beams it was found for the deflections that the asymmetric reinforcements provided reductions of up to 31.5% and the cases with symmetric reinforcements were more efficient, with deflection reductions of up to 45%. In comparison to the symmetric arrangement of the bars, the asymmetric distribution provided a reduction of up to 10.5% in the normal stress of the glulam beam compression zone. The asymmetrically arranged reinforcement effectively contributed to increasing the stiffness of the beam and was more efficient in reducing normal stresses in the compressive zone, thus preventing the initial yielding of the wood.

Glued-Laminated Timber (GLULAM) is a widely-used building material, popular for its strength, durability, and sustainability. It is created by bonding together layers of wood, making it a common choice for civil structures. In this study, Bi-directional Evolutionary Structural Optimization (BESO) is proposed to improve the performance of GLULAM structures. By positioning steel bars within the GLULAM structure, the objective is to increase the structure's stiffness and enhance its structural integrity. To achieve this, the study introduces the concept of a sub-design domain and utilizes optimization theory to determine the optimal placement of the steel bars. The finite element problem is solved using ANSYS software, while the topological optimization problem is solved using MATLAB software. The use of sub-design domains and optimization theory enables the optimal placement of the reinforcements to be determined. The results of this study demonstrate the potential of this approach for enhancing the structural integrity and stiffness of GLULAM structures under static loads.

The dimensional variables of trees play an important role in biomechanical studies that seek to estimate the risk of falls, since they influence their biomechanical behavior in relation to the forces to which they are subjected, and therefore, their safety factor. The aim of this research is to evaluate the effect of dimensional variables of trees on their mechanical behavior. A finite-element model was used to perform linear static analysis. The wood from the tree was considered clean, and the architectural model was based on dimensional variables of species commonly used in urban afforestation in São Paulo, Brazil. Different slenderness, tapering, height, and load level were used to analyze the tree mechanical behavior. The numerical-simulation model facilitates the evaluation of the influence of dimensional parameters of trees on deflections and stresses. The behavior of the deflections varies according to height, diameter, and loading level. Since the model considers the geometric variations of the section, the stresses show smooth variations along the trunk. The maximum module values of positive and negative stresses are not equal, and can undergo sudden variations in position along the trunk when local maximum stresses become global maximums.

This paper presents an evolutionary structural topology optimization method for the design of completely submerged buoyant modules with design-dependent fluid pressure loading. This type of structure is used to support offshore rig installation and pipeline transportation at all water depths. The proposed optimization method seeks to identify the buoy design that has the highest stiffness, allowing it to withstand deepwater pressure, uses the least material and has a minimum prescribed buoyancy. Laplace's equation is used to simulate underwater fluid pressure, and a polymer buoyancy module is considered to be linearly elastic. Both domains are solved with the finite element method. Using an extended bi-directional evolutionary structural optimization (BESO) method, the design-dependent pressure loads are modelled in a straightforward manner without any need for pressure surface parametrization. A new buoyancy inequality constraint sets a minimum required buoyancy effect, measured by the joint volume of the structure and its interior voids. Solid elements with low strain energy are iteratively removed from the initial design domain until a certain prescribed volume fraction. A test case is described to validate the optimization problem, and a buoy design problem is used to explore the features of the proposed method.