研磨片用胶粘剂(底胶)配方的回归设计研究

作者采用回归设计方法，试验研究了研磨片生产用胶粘剂配方的数学模型，由此计算出较优化的配方组成。首先根据以往的胶结与磨削试验经验，确认研磨片底胶的粘结强度与配方中主粘结剂、填料、触变剂的用量密切相关，确立本次回归设计研究中上述三组份的用量范围，然后基于这个用量范围采用对称单纯形回归设计方法，试验研究配方数学模型，取极大值粘结强度的配方为配方组成。其结果：主粘结剂（DZ－3水溶性酚醒树脂）用量0．448，触变剂（膨润土）用量0．182，填料（轻质碳酸钙）用量0．188，水（稀释、调和剂）用量0．182，计算的底胶的粘…     

SW型研磨页轮粘接工艺的改进

介绍了树脂研磨页轮的工艺流程，分析了现工艺中存在的不足，并用正交试验方法确定了新的用胶配方。     

环氧医疗针头胶性能影响因素的研究

采用双酚A环氧树脂GELR128及双氰胺Dyhard 100S和超低温潜伏性固化促进剂FXR-1081配制了一次性注射器用单组分加热固化型环氧针头胶。通过对胶的粘度、储存期、拉拔力、耐高压蒸汽性测试以及红外光谱分析及溶血试验,研究了胶的生产工艺和配方对其性能影响。结果表明:强力搅拌再配合两道三辊机研磨可有效降低胶的粘度,缩短固化时间。当Dyhard 100S与FXR-1081的质量比为1.52:1,两者的用量为胶总质量的10.6%时,配方的各项性能均能满足客户要求,且该配方的溶血率为0,远远满足标准要求。     

NdBR用于SBR/NR/BR体系子午胎胎冠胶的配方研究

采用均匀设计法设计了将NdBR用于SBR/NR/BR及白炭黑炭黑并用体系的子午线轮胎胎冠配方,用SAS统计回归分析软件对硫化胶主要物理机械性能进行逐步回归,得到性能与主要影响因素的回归方程,并对其进行验证,同时用其指导配方改进。结果表明,采用均匀试验和SAS回归分析得到的回归方程可以较好的预测该配方体系硫化胶的性能,指导配方改进。     

拖车用球铰的耐疲劳性能研究

探讨了拖车用球铰在试验室疲劳破坏的原因，研究拖车用球铰胶料配方中生胶、补强体系对产品的疲劳性能影响。通过产品的疲劳试验，得出了设计此类产品配方中生胶、补强体系的一些规律。     

均匀试验设计法在轮胎配方设计中的应用

均匀试验设计法是只考虑试验点在试验范围内均匀分布的一种试验设计方法，具有试验次数少、周期短、结果分析精确的特点；应用该设计法试验优选出来的配方完全达到了配方设计要求，当胎面胶中胶粉用量扩大到２０份后，胶料及成品胎的物理机械性能均较好，成品胎的耐久性能良好，实际行驶里程基本接近正常生产胎水平，并降低了胶料成本。     

数据处理组合法在橡胶配方设计回归建模中的应用

通过均匀设计安排橡胶配方试验，进而用数据处理组合方法（ＧＭＤＨ）建立高精度的回归模型。丁基橡胶配方实例表明，ＧＭＤＨ是目前较好的一种橡胶配方回归设计方法。     

在内层胶中提高合成橡胶用量降低含胶率的研究

将内层胶配方中合成橡胶用量由原来的30份提高到40份，通过改变炭黑的品种、添加5份白炭黑等方法降低原生产配方的含胶率。试验结果表明，通过配方调整，试验胶料的工艺性能、物理性能和实际使用性能与原配方生产的内层胶接近。     

数据处理组合法在橡胶配方设计回归模中的应用

通过均匀设计安排橡胶配方试验，进而用数据处理组合方法（ＧＭＤＨ）建立高精度的回归模型。丁基橡胶配方实例表明，ＧＭＤＨ是目前较好的一种橡胶配方回归设计方法。     

应用氯化丁基橡胶提高水胎使用寿命

采用NR／CIIR并用对水胎胶料配方进行改进，并与生产配方进行对比试验。结果表明：NR／CIIR并用配方胶料的拉伸强度、扯断伸长率、300％定伸应力和硬度等物理性能与生产配方胶料相近，撕裂强度和抗屈挠性能明显提高，扯断永久变形减小。水胎包皮胶和修补胶采用NR／CIIR并用配方、内层胶采用生产配方后，水胎的使用寿命明显提高，且工艺性能良好，无脱层和起皮现象发生，综合效益显著。     

Stress estimation of joints having adherends with different curvatures bonded with viscoelastic adhesives

The residual stresses in an adhesive layer between adherends with different curvatures were investigated analytically assuming the adherends as linear elastic beams and the adhesive layer as linear viscoelastic springs. A governing equation giving the time variation of adhesive thickness caused by the viscoelastic deformation is presented. The equation is an ordinary differential equation of the 4th order including a convolution equation of the creep compliance or the relaxation function equivalent to the linear viscoelastic characteristics of the adhesive. The equation gives also the distribution of a normal stress perpendicular to the interface between the adhesive and the adherends.The governing equation can be transformed into a complex number domain s by the Laplace transform, but it is difficult to solve generally the transformed equation in the s domain. However, when the adherends are long enough, the transformed equation at the end of the joint can be expressed in a simple form that can be treated analytically. In this case, the autoconvolution of the stress variation with time at the joint end is in proportion with the time integrals of the relaxation function of the adhesive. Therefore, the residual stress in the adhesive layer can be calculated by a numerical integration and a numerical auto-deconvolution, which is easier than other numerical calculations.This method has also another advantage in which the relaxation function or the creep compliance of the adhesive can be applied directly to the calculation without any mechanical analogy expressed with springs or dashpots of the adhesive's characteristics. The applicable region of the method, however, is limited by the necessary condition of long adherends.     

Shear testing of thick adhesive layers using the ENF-specimen

An existing experimental method to determine cohesive laws for adhesive layers loaded in shear is further developed. The method is based on differentiation of the energy release rate (ERR) with respect to the adhesive shear deformation at the crack tip. The test geometry used is an ENF-specimen for which the adherends are assumed to deform linearly elastic. The original method is expanded to account for situations where the thickness of the adhesive layer is not negligible as compared to the adherend thickness. To this end, a novel mathematical expression for the energy release rate (ERR) is derived. No assumptions on the form of the cohesive law are made; it is implicitly included in the derivation. The expression for the ERR contains the applied load and the shear deformation of the adhesive layer at the initial position of the crack tip, in addition to geometrical properties and the elastic modulus of the adherend material. Numerical simulations are performed to verify the accuracy of the mathematical expression for the ERR. Preliminary results from experiments performed on an epoxy adhesive are presented. The cohesive law of the adhesive layer is extracted by using a blunted crack tip. Verifying simulations confirm that the local pre-fracture behavior is accurately captured.     

Experimental Studies of the Strength of an Adhesive Joint in a State of Combined Stress

The adhesive strength of a butt-type specimen of two cylinders is experimentally studied. Combined stresses are applied on the adhesive layer by subjecting the specimen to combined axial load, torsion and internal pressure. The effects of the surface roughness, the thickness of adhesive layers and the combined stresses on the adhesive strength are examined for the specimens of various metals bonded with epoxy resin. The adhesive failure locus under the combined stress state are represented by a polynominal equation of stress tensors.     

Non-linear Modeling of Tubular Adhesive Scarf Joints Loaded in Tension

In this paper, a simple analytical model is developed to determine the adhesive shear strain distribution of a tubular adhesive scarf joint loaded in tension. The approach is an extension of the original well-recognized Volkersen's shear lag analysis for a shear loaded joint, which is frequently applied to adhesively-bonded joints. A mathematical representation consisting of linear and exponential functions is employed to model the elastic–plastic behavior commonly observed in structural adhesives. The governing equation is found to be in the form of a non-linear second-degree ordinary differential equation with variable coefficients. A numerical method required for solving this equation is also introduced. Numerical predictions of shear strain distributions are compared with results from non-linear Finite Element Analysis (FEA), utilizing the commercially available software, ANSYS 5.6, a general-purpose software system. It is shown that both the linear and non-linear approximate solutions are closely comparable with the FEA results for a 10°-scarf angle and elastic isotropic adherends. In concurrence with previous work on flat adherends, the present work demonstrates that the scarf joint develops more uniform shear stress and strain distributions with a consequent reduction in peak values than those for the conventional lap joint. In contrast, the conventional lap joint with the equivalent bonded surface area experiences a more substantial elastic trough, which can provide a more stable configuration for, sustained long term loading applications.     

Non-linear Modeling of Tubular Adhesive Scarf Joints Loaded in Tension

In this paper, a simple analytical model is developed to determine the adhesive shear strain distribution of a tubular adhesive scarf joint loaded in tension. The approach is an extension of the original well-recognized Volkersen's shear lag analysis for a shear loaded joint, which is frequently applied to adhesively-bonded joints. A mathematical representation consisting of linear and exponential functions is employed to model the elastic-plastic behavior commonly observed in structural adhesives. The governing equation is found to be in the form of a non-linear second-degree ordinary differential equation with variable coefficients. A numerical method required for solving this equation is also introduced. Numerical predictions of shear strain distributions are compared with results from non-linear Finite Element Analysis (FEA), utilizing the commercially available software, ANSYS 5.6, a general-purpose software system. It is shown that both the linear and non-linear approximate solutions are closely comparable with the FEA results for a 10°-scarf angle and elastic isotropic adherends. In concurrence with previous work on flat adherends, the present work demonstrates that the scarf joint develops more uniform shear stress and strain distributions with a consequent reduction in peak values than those for the conventional lap joint. In contrast, the conventional lap joint with the equivalent bonded surface area experiences a more substantial elastic trough, which can provide a more stable configuration for, sustained long term loading applications.     

Stress Distribution and Strength of T-type Adhesive Joint with Reinforcement for Bending Moment

The stress distribution in the adhesive layer of T-type adhesive-bonded butt joint between rigid adherends has been measured experimentally, and the equation relating the maximum stress in the adhesive layer to the bending moment applied to the joint and to the joint dimensions was derived. The equation is used to calculate the adhesive strength of a T-type joint from the measured breaking load. These strengths show reasonable agreement with experimental values.

The distribution in the adhesive layer of a T-type adhesive joint with the reinforcement having the section of a right-angled isosceles triangle has been measured experimentally. The strength efficiency of the reinforcement η and the strengthening magnification of the reinforcement μ are discussed geometrically comparing with the equation. The values of η and μ measured by the experiments showed good agreement with the values obtained geometrically.     

Dielectric Monitoring of the Bonding Process

The changes in the dielectric properties of a curing thermoset adhesive can be correlated with the chemical and rheological changes that occur during the cure. The progress towards the use of these real time events to control the bonding process is discussed. The primary mathematical relationships are described, the influence of chemical structure is discussed, monitoring under shop conditions is demonstrated and a correlation between the dielectric signal, heat of reaction and wetting angle is developed for a specific adhesive.     

Effect of a thin plastic adhesive layer on the stress singularities in a bi-material wedge

Geometric singularities for perfect bond constitute a fairly well explored area in linear elasticity. In this paper, an effect of a thin plastic adhesive layer on the singular stress field at the interface corner of a glued bi-material wedge is studied within a simple model. Following the conventional one-dimensional analysis of bonded joints, the adhesive layer is treated as a layer of displacement discontinuity between two materials. A new characteristic equation for the determination of the characteristics of the singular stress field is derived based on the classical works of Williams and Bogy. The new characteristic equation is studied for certain particular composites and angles, which commonly occur due to joining dissimilar materials. The focus of this paper is the problem associated with elimination of the singular stress field, with the goal of providing an approach for designing singular-free adhesive joints.     

An Analysis of the Curling Phenomenon in Viscoelastic Bimaterial Strips

A mathematical analysis is performed to obtain relations for the radius of curvature and flexural moments for initially stretched bimaterial strips in which at least one of the materials exhibits viscoelastic behavior. One practical application of this analysis is for pressure sensitive tapes. Consequently, the radius of curvature and flexural moment relations are obtained as functions of backing and adhesive thicknesses and moduli for typical pressure sensitive tapes. The analysis shows that the flexural moment decreases as the backing thickness and/or backing modulus increase. Furthermore, the flexural moment decreases as the adhesive thickness and/or adhesive modulus decreases.