4 results about "Moment equilibrium" patented technology

The invention relates to construction and application of a mesoscopic nonlinear fracture model for predicting rock fracture characteristics based on seamless Brazilian discs. Aiming at the technical problems that in the prior art, tensile strength and fracture toughness need to be tested separately, size effect exists and prefabricated crack introduction errors exist, a microscopic nonlinear fracture model is constructed, the virtual crack propagation amount is calculated according to the size of a test piece and the maximum particle size of rock, then nominal stress is deduced through a moment balance equation, and the tensile strength and the fracture toughness are tested separately. And finally, synchronously solving the tensile strength ft and the fracture toughness KIC without the size effect. According to the invention, a single test replaces two traditional tests, cracks do not need to be prefabricated, the test efficiency and accuracy are remarkably improved, and reliable material parameters are provided for engineering application.

This invention provides a method for calculating the side bending deformation of thick plates with large bevels. Based on the principle of thermo-mechanical coupling, this method first derives the deformation curve using a temperature field distribution formula. Then, iterative calculations are performed using an assumed initial deformation, and the results are verified through the balance of internal forces and moments to ultimately obtain the deformation curvature. This method incorporates heat input, material properties, and structural constraints into the calculation system, enabling quantitative analysis of side bending deformation. This calculation method provides a theoretical basis, overcoming the limitations of traditional methods that rely on experience and cannot accurately predict deformation. Iterative verification improves calculation accuracy, ensuring that the deformation results meet mechanical equilibrium. The obtained deformation curvature data can be directly used to guide bevel design and process optimization, helping to predict and control side bending deformation before actual construction, improving shipbuilding precision and quality, and reducing rework and adjustment costs.

The shape change prediction method of the press-formed product of the present invention predicts the shape change caused by stress relaxation accompanying the passage of time after the press-formed product (1) having a punch shoulder (9) and / or a die shoulder (11) is demolded from a mold with springback generated, wherein the method includes: a step (S1) of obtaining the shape and residual stress of the press-formed product (1) immediately after springback is generated by springback analysis of the press-formed product (1); a step (S3) of setting values of residual stress that are smaller than the residual stress of the punch shoulder (9) and / or the die shoulder (11) of the press-formed product (1) immediately after springback is generated; and a step (S5) of obtaining a shape in which moment balance is achieved with respect to the press-formed product (1) in which the values of the residual stress at the punch shoulder (9) and / or the die shoulder (11) are set to be reduced in relaxation.

The present invention relates to a method for predicting a shape change of a press-formed product, which predicts a shape change of a lengthwise end portion side twist caused by stress relaxation with the passage of time after ejection from a mold and springback, for a press-formed product (1) having a U-shaped cross-sectional shape having a ceiling portion (3) and a pair of lengthwise wall portions (5) and including a shape curved along a lengthwise direction in plan view, including: a process (S1) of acquiring a shape and a residual stress of the press-formed product (1) immediately after springback; a process (S3) of setting a value of a stress that is less than a residual stress immediately after springback, for either one of the pair of lengthwise wall portions (5) of the press-formed product (1) immediately after springback; and a process (S5) of finding a shape of a force moment balance for the press-formed product (1) for which the value of the stress that is less than the residual stress immediately after springback is set.