A new modal-based damage location indicator

Vibration-based damage detection techniques use the change in modal data as an indicator to assess damages in the structure. Knowing the structural dynamic characteristics of the healthy and damaged structure, the estimation of the damage location and severity is possible by solving an inverse problem. This paper presents a mathematical expression relating damage location and depth to the frequency shifts of the bending vibration modes. This expression permits the extraction of a series of coefficients that characterize each damage location and are independent of the damage severity. The vector aggregating these coefficients for a given location constitutes a Damage Location Indicator (DLI) that unambiguously characterizes the position of a geometrical discontinuity in the beam. A set of vectors typifying all locations along the beam may be used as patters opposable to the damage signature found by measurements. The similarity between the signature and one of the patterns indicates the location of damage

Geometrically nonlinear isogeometric analysis of laminated composite plates based on higher-order shear deformation theory

In this paper, we present an effectively numerical approach based on isogeometric analysis (IGA) and higher-order shear deformation theory (HSDT) for geometrically nonlinear analysis of laminated composite plates. The HSDT allows us to approximate displacement field that ensures by itself the realistic shear strain energy part without shear correction factors. IGA utilizing basis functions namely B-splines or non-uniform rational B-splines (NURBS) enables to satisfy easily the stringent continuity requirement of the HSDT model without any additional variables. The nonlinearity of the plates is formed in the total Lagrange approach based on the von-Karman strain assumptions. Numerous numerical validations for the isotropic, orthotropic, cross-ply and angle-ply laminated plates are provided to demonstrate the effectiveness of the proposed method

Legal and Non-legal Agricultural Practices: Toward a Sustainable Future in Malaysia\u27s Palm Oil Industry

As a major global producer of palm oil products, Malaysia is familiar with criticisms of its palm oil cultivation, poor agricultural practices and decisions during the planting process. Loss of biodiversity and deforestation resulting from unsustainable palm oil practices are perceived as major setbacks for the environment in Malaysia. However, at the same time as Malaysia stands committed to the palm oil industry and its contribution to job growth and poverty reduction, the relevant stakeholders are creating strategies for sustainable production. Together with relevant environmental laws to prevent and control impacts from climate change, loss of biodiversity and deforestation, environmental impact assessment (EIA) procedures to limit environmental impacts are also being applied. Many legal and non-legal measures to ensure sustainable palm oil production practices have been continuously debated, created or implemented over the past decades. These include certification schemes, penalties for environmental offenses, imposing environmental taxes or incentives as corrective and rehabilitative tools, and contributions to an Environmental Fund, as provided in the Environmental Quality Act (EQA) 1974. Furthermore, any new initiatives must ensure that palm oil cultivation practices adhere to and embrace the principles envisaged in the UN Sustainable Development Goals (SDGs) 2030, Roundtable Sustainable Palm Oil (RSPO), and Malaysia Sustainable Palm Oil (MSPO), in order to achieve SDGs 2030