This paper studied the bending analysis of an isotropic rectangular plate for the effects of aspect ratio, shear and deflection on the critical lateral load of the plates using the polynomial shear deformation theory (PSDT). One of the plate is clamped at opposite edge clamped and the other opposite edge simply supported (CSCS). The other of the plate is simply supported at the first and fourth edge, clamped at second edge and free of support at the third edge (SCFS). Direct variational method of analysis was adopted using straindisplacement expressions to obtain the direct governing equations for the determination of the coefficient of deflection and shear deformation along the direction of x and y coordinate. From the established equation, a new model for determination of the critical lateral imposed load of the plate is developed. The study revealed that: (i) as the specified thickness of the plate increases, the value of critical lateral imposed load increase (ii) the critical lateral imposed load decrease as the plates span increases. Numerical comparison was conducted to verify and demonstrate the efficiency of the present theory. The result obtained are in good agreement with those in the literature.

In this paper, a new polynomial shear deformation theory for the static flexural analysis of anisotropic rectangular thick plate was developed. The plate which carries a uniformly distributed load is clamped on the three edges, and free of support on the other edge (CCFC), is analyzed to determine the in-plane displacement, vertical displacement, bending moment, and shear force, bending and transverse shear stress. The General variation approach was used to obtain the general governing equation and its associated boundary conditions, thereafter the coefficient of deflection and shear deformation along the direction of x and y coordinate was determined by minimizing the energy equation obtained using the new established theory. The study revealed that: (i) as the displacement and stress decrease, the plate's span-thickness ratio increases (ii) as the length to breadth ratio of the plate increases, the value of displacement and stresses increase. To validate the theory, the numerical results are obtained and compared with an available solution in the literature. The result showed good agreement with those in the literature.

This paper was based on the application of novel breadfruit peel fiber (BFPF), a cheap agro-waste as reinforcer in low-density polyethylene matrix (LDPE) to produce breadfruit peel fiber-low-density-polyethylene composite (BFPF-LDPE) for industrial production. To achieve this, the influence of BFPF weight at different treatment routes on the mechanical properties and water absorption resistance of LDPE was examined. The BFPF was modified with sodium hydroxide (MS), sodium hydroxide/acetic acid (AM) and sodium hydroxide/acetic acid/maleated polyethylene (MM). The results showed that the treatment of BFPF with sodium hydroxide/acetic acid/maleated polyethylene gave better properties than composites produced with either sodium hydroxide or combination of sodium hydroxide/ acetic acid treatment, while untreated (UM) composite provided the poorest. This is a result of anhydride radical in MM which is absent in AM and MS. However, the tensile and impact strength for the crude LDPE indicated higher values than UM, MS, AM and MM of BFPF-LDPE composite, respectively. Furthermore, the tensile modulus, flexural strength and hardness of BFPF-LDPE composite after inclusion of UM, MS, AM and MM showed immense improvement as compared to the raw LDPE. The modified BFPF enhanced sorption resistance of the BFPF-LDPE composite. Therefore, the BFPF-LDPE composite of MM can be applied as an alternative material for the replacement of particle board in construction and automobile parts.

In this study, the ultimate tensile strength (UTS), elongation (ELG) and tensile modulus (TEM) of a recycled low-density polyethylene groundnut shell fiber composite (r-LDPE/GSF) were modeled and simulated when considered particle size (PS) and fiber content (FC) of groundnut shell fiber (GSF) by applying response surface techniques (RSM) for structural application. The deposit of recycled low-density polyethylene (r-LDPE) and GSF, an agro-waste, were combined in the production of r-LDPE/GSF composite at PS of 50–70 mesh (300–212 µm) and FC of 10–30 wt% of the GSF. The manufactured r-LDPE/GSF composite was tested for UTS, ELG and TEM and optimized by considering these process variables of GSF, PS and FC with RSM. The outcome indicated that at optimum condition, the UTS, ELG and TEM were 8.5072 MPa, 12.83% and 0.94007 GPa, respectively. The parameters at this point were PS and FC of 60.48 mesh (250 µm) and 30 wt%, respectively. The coefficient of determination (R 2) was close to 0.99. The percentage of relative errors between raw experimental reading and the RSM was <0.16. Based on the result of the work, the predicted RSM data on tensile properties of r-LDPE/GSF composite shows that is a potential engineering material for structural application.

The circulation of recycled low density polyethylene (r-LDPE) globally, using Nigeria as point of reference is emphasized in this work. The need for combining r-LDPE with a less expensive organic fiber as an economical alternative material in panel production for printer component to reduce waste through recycling. In this study, the particle size (PS) and fiber content (FC) of date palm wood fiber (DPWF) in a r-LDPE matrix are essential factors to be considered for optimizing flexural strength (FS), flexural modulus (FM) and Izod impact strength (IIS) of r-LDPE-DPWF (recycled low density polyethylene-date palm wood fiber) composite for producing printer components. The variant FC and PS of the DPWF was compounded in r-LDPE matrix to optimize the FS, FM and IIS of r-LDPE-DPWF composite, using a central composite design (CCD) as a response surface methodology (RSM). The DPWF and r-LDPE-DPWF composite were analyzed by Fourier transformed infrared (FTIR). The results indicated that the FS, FM and IIS of r-LDPE-DPWF composite measured 46.66002 MPa, 1.150043 GPa and 1.99899 KJ × m-1 at optimal operation, respectively. Under these operating conditions, PS and FC were 60.78 mesh (250 μm) and 30 wt.-%, respectively. Finally, the main coefficient of determination (R2) for the factors correlated with the characteristics of the r-LDPE-DPWF composite at an approximate value of 1 with a differential error of RSM and experiment values < 0.05 %. It was concluded that the RSM model yielded the necessary parameters for the r-LDPE-DPWF composite to be considered as a potential material for printer components.